USN-7849-1: libssh vulnerability

Publication date

4 November 2025

Overview

libssh could be made to crash.


Packages

  • libssh - A tiny C SSH library

Details

Philippe Antoine discovered that libssh did not properly manage memory
when calculating a session id during the key exchange process. An attacker
could possibly use this issue to cause libssh to crash, resulting in a
denial of service.

Philippe Antoine discovered that libssh did not properly manage memory
when calculating a session id during the key exchange process. An attacker
could possibly use this issue to cause libssh to crash, resulting in a
denial of service.

Update instructions

In general, a standard system update will make all the necessary changes.

Learn more about how to get the fixes.

The problem can be corrected by updating your system to the following package versions:

Ubuntu Release Package Version
25.10 questing libssh-4 –  0.11.2-1ubuntu0.1
25.04 plucky libssh-4 –  0.11.1-1ubuntu0.2
24.04 LTS noble libssh-4 –  0.10.6-2ubuntu0.2
libssh-gcrypt-4 –  0.10.6-2ubuntu0.2
22.04 LTS jammy libssh-4 –  0.9.6-2ubuntu0.22.04.5
libssh-gcrypt-4 –  0.9.6-2ubuntu0.22.04.5
20.04 LTS focal libssh-4 –  0.9.3-2ubuntu2.5+esm2  
libssh-gcrypt-4 –  0.9.3-2ubuntu2.5+esm2  
18.04 LTS bionic libssh-4 –  0.8.0~20170825.94fa1e38-1ubuntu0.7+esm5  
libssh-gcrypt-4 –  0.8.0~20170825.94fa1e38-1ubuntu0.7+esm5  
16.04 LTS xenial libssh-4 –  0.6.3-4.3ubuntu0.6+esm3  
libssh-gcrypt-4 –  0.6.3-4.3ubuntu0.6+esm3  

Reduce your security exposure

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Have additional questions?

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