Bitvise SSH Client: download ældre versioner

- SSH:
- Improved multiple avenues which a server could use to exert disproportionate memory pressure on the client.
- SFTP drive:
- The SSH Client now includes WinFsp version 2.2.26194. This addresses CVE-2026-7162, which is a local privilege escalation. Users who install the SSH Client with the SFTP drive feature are recommended to update, especially on multi-user systems. The SFTP drive feature is available if Install WinFsp is selected when installing.
- The UNC path used by the SFTP drive is now configurable. This makes it practical to configure a UNC path for access by other users on the system.
- The SFTP drive can now be configured to expose only the UNC path, without assigning a drive letter.
- The SFTP drive can now be configured to provide access either to the current user, or any user on the system.

- General:
- The SSH Client is now less permissive with regard to NUL characters in protocol strings where NULs are not expected.
- When making an outgoing connection via an HTTP CONNECT proxy, the SSH Client now limits the maximum size of received HTTP headers.
- SSH:
- The SSH Client now implements a configurable timeout for the duration of the initial SSH key exchange.
- The Keep-alive / broken session detection feature now has a configurable initial timeout. Previously, it could be enabled or disabled, but the period could not be configured.
- SFTP:
- The SSH Client now implements more granular limits for the sizes of decoded SFTP strings.
- The SSH Client now limits the maximum backlog of unfulfilled handle close operations.
- Graphical client:
- Restoring the SSH Client main window after it's hidden to the system tray should now work better if it was previously displayed on a second monitor that was unplugged.
- Graphical terminal:
- The window title and scroll bar for the SSH Client's graphical terminal window now support dark mode.
- New Remote Desktop:
- The RDP profile signing feature introduced in version 9.61 could cause Remote Desktop to exit abruptly on some systems. The implementation of this feature should now be more resilient.
- sftpc:
- The sftpc command-line client now supports Stat and RealPath commands.
- A long-standing issue prevented auto-completion from working correctly when a switch parameter was passed before a path. Fixed.
- stermc:
- The stermc command-line client now supports a pass-through rendering mode for Windows Terminal. This substantially improves stermc usability with Windows Terminal.
Pass-through mode cannot be used with bvterm. Pass-through mode does not support printable session recording, but supports full session recording which includes escape sequences.

- SSH:
- The SSH Client will no longer display infinite user authentication banners if the server keeps sending them. If the server sends additional banners after the first, subsequent banners are discarded with a single log warning.
- The SSH Client now enforces a maximum per-connection channel limit. Currently, the SSH Client limit is fixed at 1000 channels per connection.
- sexec:
- When stdout is redirected, the sexec command-line client now writes any errors and help text to stderr instead of stdout.
This should make errors easier to diagnose when sexec is used with Git, or with other applications which expect stdout to conform to an application protocol.
- Dynamic port forwarding:
- Hardened surfaces which could allow runaway memory use when the SSH Client is configured to act as a SOCKSv4 or HTTP CONNECT proxy. Implemented a timeout for the initial proxy request.
- When using dynamic port forwarding (proxy forwarding) for server-to-client connections, bind addresses could be matched incorrectly. Fixed.
- FTP-to-SFTP bridge:
- The FTP bridge now requires that passive-mode data connections arrive from the same client IP address as the FTP control connection.
- FTP control connection replies can now correctly contain UTF-8 characters, as advertised.
- Double quotes are now escaped if they appear in quoted paths sent in FTP control connection replies.
- CR and LF characters are now removed if they appear in file or directory names sent in directory listings.
- Control connection commands containing NUL bytes are no longer accepted.
- Graphical SFTP:
- Disabled icons are now slightly less terrible on very old Windows versions.

- General:
- The SSH Client is now more defensive against processing patterns which could cause the SSH Client to allocate large amounts of memory.
- Remote Desktop:
- Since an April 2026 Windows update, the Windows Remote Desktop client (MSTSC) now displays a warning when started with an RDP profile which does not carry a trusted signature. The SSH Client's New Remote Desktop feature starts MSTSC using a temporary profile, so this warning displays each time New Remote Desktop is used.
To improve usability, the SSH Client now supports RDP profile signing. The SSH Client offers to generate a local self-signed certificate specific for the current Windows user. If confirmed by the user, the client sets up the certificate in the user's Trusted Root Certification Authorities. The SSH Client can then start Remote Desktop using a signed temporary profile.
The Custom setting for MSTSC command-line parameters cannot be used when RDP signing is enabled. MSTSC rejects command-line overrides for signed profiles. Such custom settings can be configured using Custom RDP settings. The SSH Client includes these settings in the signed profile.

- When using a file-based profile, the SSH Client now includes the profile name in the Remote Desktop window title.
- SFTP drive:
- The SSH Client now includes WinFsp version 2.2.26112. This addresses CVE-2026-3006, which is a local privilege escalation. Users who install the SSH Client with the SFTP drive feature available ("Install WinFsp" enabled when installing), especially on multi-user systems, are recommended to update.
- When opening or creating a file, the SSH Client now strips access flags not supported by the SFTP server. In previous versions, such access flags could cause actions on the SFTP drive to fail - for example, copy and paste to an SFTP drive.
- Graphical client:

- The SSH Client's main window now restores as intended when the last Remote Desktop connection, SFTP window or terminal window is closed.

- In version 9.51, the implementation of dark mode support accidentally disabled the ability to configure custom colors on Terminal tab > Default colors. This functionality is now restored.
- Ctrl+Backspace is now more consistently supported across input elements.
- UI improvements, including for issues related to dark mode.
- SFTP:
- When displaying a vendor-id extension, the SSH Client would incorrectly display the product name twice, instead of displaying the product name and version. Fixed.

- Installation:
- The SSH Client installer still requires administrative rights for installation, but can now be run without administrative rights for help with command-line parameters. Users who are preparing the SSH Client for portable use no longer need administrative rights to extract files in the installer.
- Authentication:
- If the user runs the PuTTY authentication agent using pageant --unix, and configures the SSH_AUTH_SOCK environment variable with the path to the Unix socket file, the SSH Client now detects this as an unsupported mechanism, and still tries connecting to the Windows OpenSSH agent. The SSH Client already connects to the PuTTY agent using the PuTTY mechanism, so it doesn't need a second connection to the same agent.
In previous versions, this configuration would cause the SSH Client to display an error message, and it would not further try to connect to the Windows OpenSSH agent. The connection to the PuTTY agent would still work using the PuTTY mechanism.
- SFTP GUI:
- Switching between light mode and dark mode no longer requires the SFTP window to be closed and reopened in order to use the appropriate icons.

- Updates:
- If the administrator first installed the SSH Client with the option Create desktop icon selected, each update would re-create the desktop icon, even if it was removed. The SSH Client installer now detects that the desktop icon has been removed and will not re-create it during an update.
- In some environments, downloading a new version installer fails with Windows error code 12057 (ERROR_INTERNET_SEC_CERT_REV_FAILED). The Windows error description for this error code is misleading. The update interface now provides an error description which is hopefully more useful.
- General:
- In previous versions 9.5x, the authentication dialog did not set input focus correctly for client authentication keypairs protected by a passphrase. Fixed.
- SSH Client versions 9.5x detect and warn if there is an existing connection, by another SSH Client process, to the same server, using the same credentials. This is generally helpful, but there are usage cases which require such concurrent connections. It is now possible to disable this warning using App settings.
- SFTP Drive:
- In previous SSH Client versions, when a Windows application attempted to set file size on the SFTP drive using SetEndOfFile or a similar API, the operation would succeed, but commonly return an unsuccessful error code which incorrectly indicated an internal error. This would work with applications that don't check this error code, but would cause problems with applications that do check it. Fixed.

- Graphical UI:
- Dark mode: If the Windows color mode is set to Light or Custom; and the Windows app mode is set to Light; then list view headers, scrollbars and system menus would appear with light backgrounds instead of dark. Fixed.
- Terminal window:
- Implemented a compatibility improvement to allow the terminal window to work with Sogou Pinyin IME.
- Improved Unicode handling for characters in the last column of the window.

- Graphical SFTP:
- In previous 9.5x versions, when using dark mode, the SFTP window would hang if file icons were not yet available in the Windows Explorer icon cache.
For the technically inclined: this is an interesting interaction between the Windows function SHGetFileInfoW, which is used to retrieve file icons; and the Windows List View control, in particular when it's set to a transparent background style: LVS_EX_TRANSPARENTBKGND.
If a file icon is not yet cached by Windows, SHGetFileInfoW starts a nested message loop. This is so that the application can remain responsive during a potential extended adventure in search of the icon. In the case of the SSH Client, this nested message loop occurred in the middle of a List View paint cycle, because the List View requested an icon, and this is what caused the SSH Client to call SHGetFileInfoW. During the nested message loop, a new paint cycle is started, which is its purpose - maintaining UI responsiveness. Although List View is already in a paint cycle, the reentrant paint usually works, as long as the application has not set a transparent background. If it has, then the List View does not support reentrant paint with transparency, aborts the paint, and schedules a new paint. The new paint is scheduled in the nested message loop, which continues indefinitely until it's drained. This causes an infinite cycle of attempted and aborted paints between List View and SHGetFileInfoW.
Microsoft appears to be aware of such issues: current documentation warns that calling SHGetFileInfoW on the UI thread may cause the UI to stop responding. The SSH Client got away with this for 20 years. With version 9.55, we are replacing this with a cache component which calls SHGetFileInfoW on a background thread. As a tradeoff, this causes uncached icons to appear slightly later, when they are loaded.
Suggestion to Microsoft: Since you're already recommending applications to call SHGetFileInfoW on a background thread, just remove the nested message loop functionality from SHGetFileInfoW. It seems to be a misfeature which can cause a variety of problems. For example, stack overflow seems possible if SHGetFileInfoW keeps being called from the nested message loop again.

- Graphical terminal:
- When rendering multiple characters at a time, the SSH Client now specifies the width of each character. This avoids cumulative misalignment if Windows chooses to render text using a wider font, in particular when using bold style.

- General:
- Improved consistency of window titles.
- Graphical terminal:
- Version 9.51 introduced section-based text rendering to accommodate font ligatures. This can cause problems if Unicode characters are included in a sequence that's rendered together. All Unicode characters outside of the ASCII range are now again rendered per-character.
As a consequence, text sequences such as Hebrew will once again render left-to-right, not right-to-left. This is necessary for cursor behavior to match what is displayed when editing text in the terminal.
- The graphical terminal now supports Unicode non-spacing marks as long as they can be folded onto the preceding character. For example, the sequence "A" U+0302 U+0303 may now be rendered as the single character "Ẫ" (U+1EAA).
If non-spacing marks cannot be folded onto the preceding character, they are still rendered separately. For example, the partially invalid sequence "A" U+0303 U+0302 is now rendered as "Ã" (U+00C3), followed by a separate U+0302. Exact normalization behavior depends on the version of Windows.

- Terminal:
- In version 9.51, the terminal window in the graphical SSH Client was rendering Unicode characters incorrectly. Fixed.
- General:
- In version 9.51, the authentication dialog did not set input focus correctly. Fixed.
- If a profile is opened, the window title for the main SSH Client window now also displays the profile name when not connected.

- Automatic updates:
- Separate proxy settings can now be configured for automatic updates. This allows checks for updates, and downloads of new version installers, to use a different proxy than the one configured in Windows.
- SSH:
- Bitvise SSH Server, SSH Client and FlowSsh now support hybrid post-quantum and classical key exchange using the key exchange methods mlkem1024nistp384-sha384 and mlkem768x25519-sha256. These key exchange methods use algorithms outside of Windows cryptography. They are only available when FIPS 140 cryptography mode is not enabled in Windows. The new algorithms require Windows Vista or newer.
- The SSH Client can now be configured to Require strict key exchange. Strict key exchange is a recent SSH protocol feature supported since Bitvise software versions 9.32. It mitigates the Terrapin vulnerability in SSH implementations prior to December 2023 (CVE-2023-48795). If the SSH connection does not use strict key exchange, the encryption algorithm chacha20-poly1305 is particularly vulnerable.
- Graphical SSH Client:
- The SSH Client now supports dark mode. This can be enabled using the main SSH Client window > App settings.
- When selecting a client authentication keypair, the SSH Client now displays a truncated comment. This makes it easier to tell which key is which.
- App settings (previously, Window behavior) can now be controlled using command-line parameters. This is of particular interest for users who use -noRegistry.
- Settings for pop-up notifications can now be configured using App settings, in addition to the icon menu in the system notification area.
- The SSH Client now detects when another SSH Client instance is already connected to the same server, using the same username. This is to help users notice when they have an existing SSH Client instance hidden in the system notification area.
- When importing a client authentication keypair, the SSH Client now more thoroughly detects duplicates.
- Graphical SFTP:
- Local and Remote SFTP settings are now configurable in separate dialogs. These settings can now be edited via the SFTP window.
- Settings are now supported to express a preference whether the server should use unbuffered I/O. The preference is effective when connecting to Bitvise SSH Server 9.34 or newer, if server-side settings permit.
The sftpc command-line client supports the equivalent -noBuf switch for get and put commands since version 9.34.
- When the remote directory contains symbolic links, the SSH Client must resolve them to know if an entry is a file or a directory. This requires an SFTP request for each symbolic link. For directories that contain many symbolic links which cannot be resolved, the SSH Client now gives up if it encounters 10 failures without any successes.
- The feature to Open or Edit remote files uses a temporary local directory. If something removes this directory, the SSH Client now tries to re-create it.
- Terminal window:
- Font ligatures are now rendered, when using fonts that support them.
- Command-line clients:
- sftpc no longer reports an error if the server disconnects during the quit or exit command.
- The sexec and stermc command-line clients now support consecutive execution of multiple commands using -cmdFile=... or using multiple -cmd=... parameters.
- The sexec command-line client now supports an -inputEOL=... parameter to control how input newlines should be sent to the remote process. Default behavior remains to perform no conversion.
- The sexec command-line client now supports a -conInMode=... parameter to control how input should be read from the console (when input is not redirected from a pipe or file). Default behavior is now to read individual keystrokes and send them promptly, without local echo.
- The retry utility now supports -m=0 for infinite retries.
- Port forwarding:
- Bitvise SSH Client, stnlc and FlowSsh now support port forwarding (connection tunneling) to and from server-side Unix sockets. To use a Unix socket as the f

- Graphical SSH Client:
- When using public key authentication using a passphrase-protected key, previous SSH Client versions did not refresh client keypair information as intended. After a manual logout, the SSH Client would continue to cache the client key passphrase. If the passphrase was removed, or if it was newly set, the SSH Client did not take the new setting properly into account.
After a manual logout, client key information is now refreshed. The SSH Client will ask for the client key passphrase during the next login. For automatic reconnect, the passphrase continues to be cached, so that it does not have to be re-entered if the connection is lost and automatically restored.
- sftpc:
- The sftpc command-line SFTP client now supports the -ifExist parameter for put and get commands. When -ifExist is passed, the command completes successfully if the source of the transfer does not exist. In previous versions, a wildcard pattern needed to be used to avoid an error if there are no matches.
- Terminal:
- When recording a terminal session, the output file is now opened using the Windows flag FILE_SHARE_READ. This allows the file to be viewed in other applications while recording is in progress.

- SFTP:
- In recent versions, text mode transfers would fail if resume was enabled. Text mode is incompatible with resume, but transfers would fail for new files that do not need resume. Fixed.
- The transfer mode Text is renamed to Text Std. Updated help text related to Text Std and Auto Std.

- General:
- When loading profiles, the SSH Client now strips whitespace at the start of most strings, including Unicode whitespace.
- The SSH Client's installation directory path hijack check can now be disabled by configuring the DWORD value DisableInstDirCheck, with value 1, under the Windows registry key HKLM\Software\WOW6432Node\Bitvise. This also disables the check in recent versions of Bitvise SSH Server.
- Proxy support:
- When configured to connect via an HTTP CONNECT proxy, the SSH Client now sends an HTTP/1.1 request, including a Host header. Previous versions sent an HTTP/1.0 request (no Host header).
- Graphical SFTP:
- Cut-and-paste in the Local files pane can now move local files across drives and filesystem volumes. Directories cannot be moved in this manner.
- The Filter feature in the Local files and Remote files panes now applies to both files and directories. Previously, it would filter only files.
- Fixed additional issues in reporting of final size and reused bytes when using synchronization.

- Installation:
- When installing the FlowSshNet library component, the SSH Client installer now specifies the full path to msiexec.exe in the Windows System32 directory. This is to avoid running any unintended executable also named msiexec.exe which may have been placed in the same directory as the installer.
On a system with multiple users, administrators should never run executables from a directory where a non-administrator user can write files outside of the administrator's control.
- SFTP:
- In the sftpc command-line client, the remote directory listing commands dir and ls, and the local versions ldir and lls, now support parameters to group directories and files separately, sort by name, sort by time, or reverse sorting order.

- SSH cryptography:
- Starting with 9.43, the latest versions of Bitvise software no longer use OpenSSL:
- OpenSSL no longer supports versions 1.1.1. Our recent software versions used this to support a handful of algorithms not supported by Windows.
- There are new fixes only available in OpenSSL 3.x.
- OpenSSL 3.x promotes opaque interfaces and hides details. This is the opposite of our requirements.
- OpenSSL 3.x is even larger than 1.1.1, and dramatically increases linker bloat. Updating OpenSSL 1.1.1 to 3.4.1 increases the size of CiWinCng64.dll from 3.3 MB to 5.0 MB. Removing OpenSSL reduces the size to 1.4 MB. The difference, 3.6 MB, is a lot of complexity to support some marginal algorithms.
This change does not affect most algorithms. We support most algorithms using Windows cryptography. Only the following is affected:
- chacha20-poly1305: We now support this algorithm using public domain ChaCha20 implementations from Goll & Gueron (on most CPUs with AVX2), Daniel J. Bernstein (on CPUs without AVX2), and Poly1305 from Andrew Moon (poly1305-donna).
In new Bitvise software installations, chacha20-poly1305 is disabled by default, because it is the most susceptible to the Terrapin attack if the counterparty does not implement strict key exchange. This algorithm is secure if both parties support strict key exchange. In Bitvise software, strict key exchange is supported in versions 9.32 and newer.
- ECDSA and ECDH over the curve secp256k1: On Windows 10 and newer, and Windows Server 2016 and newer, we continue to support this curve using Windows cryptography. On these Windows versions, there is no change.
On Windows Vista to 8.1, and Windows Server 2008 to 2012 R2, secp256k1 is now supported using Crypto++ 5.6. This implementation is not constant-time, so in this case, we enable signature timing mitigations. The timing mitigations favor security over performance: a signature is delayed to take e.g. 50 ms instead of 1 ms.
In SSH, this prime field curve is rarely used. We support it for compatibility with previous versions. We originally added this curve because it is used in Bitcoin, so it is subject to intense scrutiny. However, users who want elliptic curve cryptography, but doubt the widely used NIST curves, have usually chosen Curve25519 and Ed25519.
If FIPS 140-2 cryptography is enabled in Windows, there is no change. If FIPS mode is enabled, Bitvise software already restricts itself only to algorithms supported by Windows. In this case, chacha20-poly1305 is not available, and secp256k1 is available only on Windows versions 10 and newer, which support it.
- Bitvise software versions 9.xx remain compatible with Windows XP and Windows Server 2003. To support SSH cryptography on these platforms, our installers include DLL files CiCpFips32/64.dll and CryptoPP530Fips32/64.dll. These DLLs are not used on Windows Vista and newer, but were previously installed on all Windows versions. They are now no longer installed on Windows versions where they are not used.
- SFTP:
- When resuming or updating files using hash-based synchronization, progress was being reported incorrectly. When the destination file was larger than the source, the final file size was also displayed incorrectly. Fixed.
- Terminal:
- In previous versions, the SSH Client's xterm implementation would stop parsing unrecognized CSI escape sequences at the first unrecognized byte, and render the bytes which follow. The SSH Client now continues to parse unrecognized CSI sequences according to ECMA-48, and ignores them. This avoids unexpected characters in output when a server application sends sequences which the SSH Client does not support. For example, the fish shell sends such sequences associated with the Kitty Keyboard Protocol.

FlowSshNet:
- In previous 9.xx versions, the FlowSshNet constructor Keypair.CreateFromData would block indefinitely if the application provided a passphrase-protected keypair, but the passphrase was incorrect. Fixed.