wolfSSH 1.4.15 Now Available!

Merry Christmas! The Christmas release of wolfSSH is here, version 1.4.15!

Version 1.4.15 brings with it a fix for a vulnerability, bug fixes, new features, and some enhancements as well! For a description of vulnerabilities fixed, please see our vulnerability page. New features in this release include a wolfSSH client application, support for OpenSSH-style keys, and Zephyr RTOS builds.

We also have a nice round of enhancements which range from better testing, improved portability, terminal enhancements (run vim or tmux!), and more!

A list of new features and enhancements from our ChangeLog is listed below. For a full list of fixes see our complete ChangeLog on GitHub.

Vulnerability Fix

  • Fixes a potential vulnerability described in the paper “Passive SSH Key Compromise via Lattices”. While the misbehavior described hasn’t been observed in wolfSSH, the fix is now implemented. The RSA signature is verified before sending to the peer.

    • Keegan Ryan, Kaiwen He, George Arnold Sullivan, and Nadia Heninger. 2023. Passive SSH Key Compromise via Lattices. Cryptology ePrint Archive, Report 2023/1711. https://eprint.iacr.org/2023/1711.

New Features

  • Added wolfSSH client application.
  • Added support for OpenSSH-style private keys, like those made by ssh-keygen.
  • Added support for the Zephyr RTOS.
  • Added support for multiple authentication schemes in the userauth callback with the error response WOLFSSH_USERAUTH_PARTIAL_SUCCESS.


  • Allow override of default sshd user name at build.
  • Do not attempt to copy device files. The client won’t ask, and the server won’t do it.
  • Added more wolfSSHd tests.
  • Portability updates.
  • Terminal updates for shell connections to wolfSSHd, including window size updates.
  • QNX support updates.
  • Windows file support updates for SFTP and SCP.
  • Allow for longer command strings in wolfSSHd.
  • Tweaked some select timeouts in the echoserver.
  • Add some type size checks to configure.
  • Update for changes in wolfSSL’s threading wrappers.
  • Updates for Espressif support and testing.
  • Speed improvements for SFTP. (Fixed unnecessary waiting.)
  • Windows wolfSSHd improvements.
  • The functions wolfSSH_ReadKey_file() and wolfSSH_ReadKey_buffer() handle more encodings.
  • Add function to supply new protocol ID string.
  • Support larger RSA keys.
  • MinGW support updates.
  • Update file use W-macro wrappers with a filesystem parameter.
  • Fixes

    • When setting the file permissions for a file in Zephyr, use the correct permission constants.
    • Fix buffer issue in DoReceive() on some edge failure conditions.
    • Prevent wolfSSHd zombie processes.
    • Fixed a few references to the heap variable for user supplied memory allocation functions.
    • Fixed an index update when verifying the server’s RSA signature during KEX.
    • Fixed some of the guards around optional code.
    • Fixed some would-block cases when using non-blocking sockets in the examples.
    • Fixed some compile issues with liboqs.
    • Fix for interop issue with OpenSSH when using AES-CTR.

    Visit our download page or wolfSSH GitHub repository to download the release bundle, and feel free to email us at facts@wolfSSL.com or support@wolfssl.com, or call us at +1 425 245 8247 with any questions about the wolfSSH embedded SSH library or other products.

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