CVE-2025-5372Libssh: incorrect return code handling in ssh_kdf() in libssh

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.

Timeline

Scores

EPSS (exploitation in 30 days)

0.51% · top 56% of all CVEs (12 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.0.

Affected products

• libssh · libssh

  • affected < 0.11.2

• Red Hat · Red Hat Enterprise Linux 8

  • unaffected 0:0.9.6-16.el8_10 – < *

• Red Hat · Red Hat Enterprise Linux 8

  • unaffected 0:0.9.6-16.el8_10 – < *

• Red Hat · Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support

  • unaffected 0:0.9.4-2.el8_4.2 – < *

• Red Hat · Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On

  • unaffected 0:0.9.4-2.el8_4.2 – < *

• Red Hat · Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support

  • unaffected 0:0.9.6-4.el8_6.2 – < *

• Red Hat · Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On

  • unaffected 0:0.9.6-4.el8_6.2 – < *

• Red Hat · Red Hat Enterprise Linux 8.8 Telecommunications Update Service

  • unaffected 0:0.9.6-13.el8_8.2 – < *

• Red Hat · Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions

  • unaffected 0:0.9.6-13.el8_8.2 – < *

• Red Hat · Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions

  • unaffected 0:0.9.6-3.el9_0.2 – < *

• Red Hat · Red Hat Enterprise Linux 10

  All versions: unaffected

• Red Hat · Red Hat Enterprise Linux 6

  All versions: unknown

• Red Hat · Red Hat Enterprise Linux 7

  All versions: unknown

• Red Hat · Red Hat Enterprise Linux 9

  All versions: affected

• Red Hat · Red Hat OpenShift Container Platform 4

  All versions: affected

• Red Hat · Red Hat OpenShift Container Platform 4

  All versions: unaffected

What to do

Workaround: To mitigate this issue, administrators should ensure that libssh is built against OpenSSL version 3.0 or later. This change eliminates the return code mismatch and prevents the erroneous use of uninitialized key material. It is also strongly recommended to apply vendor supplied patches or update to the latest libssh security release as soon as possible.

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• EUVD EUVD-2025-19931 (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2025-5372](https://cveledger.app/badge/CVE-2025-5372.svg)](https://cveledger.app/cve/CVE-2025-5372)

Record last updated 5 Nov 2026, 15:37 UTC.