What’s Vulnerable › Vulnerabilities
CVE-2023-6918: Libssh: missing checks for return values for digests
- Severity: medium (CVSS 5.3 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 1.4% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2023-12-19 · updated 2026-06-17
- Weakness: CWE-252
Description
A flaw was found in the libssh implements abstract layer for message digest (MD) operations implemented by different supported crypto backends. The return values from these were not properly checked, which could cause low-memory situations failures, NULL dereferences, crashes, or usage of the uninitialized memory as an input for the KDF. In this case, non-matching keys will result in decryption/integrity failures, terminating the connection.
Affected products
- Fedoraproject Fedora: 38, 39
- libssh: from 0.9.0 before 0.9.8; from 0.10.0 before 0.10.6 — fixed in 0.10.6, 0.9.8
- Red Hat Enterprise Linux: 8.0, 9.0
How to fix
Upgrade to a fixed version: libssh 0.10.6, 0.9.8. Check the vendor advisory for mitigations.
References
- https://access.redhat.com/errata/RHSA-2024:2504
- https://access.redhat.com/errata/RHSA-2024:3233
- https://access.redhat.com/security/cve/CVE-2023-6918
- https://bugzilla.redhat.com/show_bug.cgi?id=2254997
- https://www.libssh.org/2023/12/18/libssh-0-10-6-and-libssh-0-9-8-security-releases/
- https://www.libssh.org/security/advisories/CVE-2023-6918.txt
- https://access.redhat.com/errata/RHSA-2024:2504
- https://access.redhat.com/errata/RHSA-2024:3233
- https://access.redhat.com/security/cve/CVE-2023-6918
- https://bugzilla.redhat.com/show_bug.cgi?id=2254997
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/LZQVUHWVWRH73YBXUQJOD6CKHDQBU3DM/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/MKQRBF3DWMWPH36LBCOBUTSIZRTPEZXB/
Get alerted when CVE-2023-6918 or the next vulnerability affects your stack