Inefficient Regular Expression Complexity Affecting libssh package, versions <0.9.3-2ubuntu2.5+esm3


Severity

Recommended
0.0
medium
0
10

Based on Ubuntu security rating.

Threat Intelligence

EPSS
0.22% (13th percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications
  • Snyk IDSNYK-UBUNTU2004-LIBSSH-15356996
  • published26 Feb 2026
  • disclosed26 Mar 2026

Introduced: 26 Feb 2026

CVE-2026-0967  (opens in a new tab)
CWE-1333  (opens in a new tab)

How to fix?

Upgrade Ubuntu:20.04 libssh to version 0.9.3-2ubuntu2.5+esm3 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream libssh package and not the libssh package as distributed by Ubuntu. See How to fix? for Ubuntu:20.04 relevant fixed versions and status.

A flaw was found in libssh. A remote attacker, by controlling client configuration files or known_hosts files, could craft specific hostnames that when processed by the match_pattern() function can lead to inefficient regular expression backtracking. This can cause timeouts and resource exhaustion, resulting in a Denial of Service (DoS) for the client.

CVSS Base Scores

version 3.1