Vulnerability in Libssh
CVE-2025-5372
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.0 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L.
EPSS exploit prediction
EPSS: 0.005 (37.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 38th percentile — 37.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.005 · change: +0.000
Affected products
- Libssh — versions 0
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8 — versions 0:0.9.6-16.el8_10
- Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support — versions 0:0.9.4-2.el8_4.2
- Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On — versions 0:0.9.4-2.el8_4.2
- Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support — versions 0:0.9.6-4.el8_6.2
- Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On — versions 0:0.9.6-4.el8_6.2
- Red Hat Enterprise Linux 8.8 Telecommunications Update Service — versions 0:0.9.6-13.el8_8.2
Weakness classification (CWE)
Public proof-of-concept exploits
References
- access.redhat.com/errata/RHSA-2025:21977 (vendor-advisory)
- access.redhat.com/errata/RHSA-2025:23024 (vendor-advisory)
- access.redhat.com/security/cve/CVE-2025-5372 (Third Party Advisory, vdb-entry)
- bugzilla.redhat.com/show_bug.cgi (issue-tracking, Third Party Advisory, Issue Tracking)
- access.redhat.com/errata/RHSA-2026:20610 (vendor-advisory)
- access.redhat.com/errata/RHSA-2026:24349 (vendor-advisory)
- access.redhat.com/errata/RHSA-2026:25911 (vendor-advisory)
Frequently asked questions
- What is CVE-2025-5372?
- CVE-2025-5372 is a medium-severity vulnerability in Libssh, classified under Incorrect Calculation. CVSS score: 5.0/10. Published 2025-07-04.
- How severe is CVE-2025-5372?
- Medium severity. CVSS v3 base score is 5.0 out of 10.
- Is CVE-2025-5372 known to be exploited?
- 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.