USN-8722-1: libssh2 vulnerabilities

Publication date

3 September 2026

Overview

Several security issues were fixed in libssh2.


Packages

  • libssh2 - Client-side C library implementing the SSH2 protocol

Details

It was discovered that libssh2 incorrectly handled certain SFTP server
responses. A remote attacker controlling an SSH server could use this issue
to cause libssh2 to crash or possibly execute arbitrary code.
(CVE-2026-66032)

It was discovered that libssh2 incorrectly handled AES-GCM cipher
negotiation. A remote attacker controlling an SSH server could possibly use
this issue to cause libssh2 to crash, resulting in a denial of service.
(CVE-2026-66033)

It was discovered that libssh2 incorrectly handled Encrypt-then-MAC cipher
negotiation. A remote attacker controlling an SSH server could use this
issue to cause libssh2 to crash or possibly execute arbitrary code.
(CVE-2026-66035)

It was discovered that libssh2 incorrectly handled certain SFTP server
responses. A remote attacker controlling an SSH server could use this issue
to cause libssh2 to crash or possibly execute arbitrary code.
(CVE-2026-66032)

It was discovered that libssh2 incorrectly handled AES-GCM cipher
negotiation. A remote attacker controlling an SSH server could possibly use
this issue to cause libssh2 to crash, resulting in a denial of service.
(CVE-2026-66033)

It was discovered that libssh2 incorrectly handled Encrypt-then-MAC cipher
negotiation. A remote attacker controlling an SSH server could use this
issue to cause libssh2 to crash or possibly execute arbitrary code.
(CVE-2026-66035)

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
26.04 LTS resolute libssh2-1t64 –  1.11.1-1ubuntu0.26.04.4
24.04 LTS noble libssh2-1t64 –  1.11.0-4.1ubuntu0.24.04.4

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