# CVE-2023-6918: Libssh: missing checks for return values for digests

Status: published. Published: 2023-12-18. Updated: 2026-11-06.

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.

## Remediation

- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. (source: CNA: redhat)

## Affected products and versions

- Red Hat / Red Hat Enterprise Linux 8 (libssh): ≥ 0:0.9.6-14.el8; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (libssh): ≥ 0:0.10.4-13.el9; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 6 (libssh2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 7 (libssh): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 7 (libssh2): Version range not reported. Source: CNA: redhat

## Severity and prioritization

- CVSS 3.1: 3.7 (low); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L; source: CNA: redhat

- CISA KEV: No listing in collected sources

- EPSS: 1.41% as of 2026-11-05; percentile 72.74%

- SSVC: Not available

- Weaknesses: CWE-252

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://access.redhat.com/errata/RHSA-2024:2504 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2024:3233 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/security/cve/CVE-2023-6918 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2254997 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

- https://www.libssh.org/2023/12/18/libssh-0-10-6-and-libssh-0-9-8-security-releases/ (CNA: redhat)

- https://www.libssh.org/security/advisories/CVE-2023-6918.txt (CNA: redhat)

- https://access.redhat.com/errata/RHSA-2024:2504 (ADP: CVE; vendor-advisory, x_refsource_REDHAT, x_transferred)

- https://access.redhat.com/errata/RHSA-2024:3233 (ADP: CVE; vendor-advisory, x_refsource_REDHAT, x_transferred)

- https://access.redhat.com/security/cve/CVE-2023-6918 (ADP: CVE; vdb-entry, x_refsource_REDHAT, x_transferred)

- https://bugzilla.redhat.com/show_bug.cgi?id=2254997 (ADP: CVE; issue-tracking, x_refsource_REDHAT, x_transferred)

- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/LZQVUHWVWRH73YBXUQJOD6CKHDQBU3DM/ (ADP: CVE; x_transferred)

- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/MKQRBF3DWMWPH36LBCOBUTSIZRTPEZXB/ (ADP: CVE; x_transferred)

- https://www.libssh.org/2023/12/18/libssh-0-10-6-and-libssh-0-9-8-security-releases/ (ADP: CVE; x_transferred)

- https://www.libssh.org/security/advisories/CVE-2023-6918.txt (ADP: CVE; x_transferred)

- https://security.netapp.com/advisory/ntap-20250214-0009/ (ADP: CVE)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2023-6918; retrieved 2026-11-06; source updated 2026-11-06

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2023-6918; retrieved 2026-11-06; source updated Not reported

Revision: 4f400ae73681dd15beab2e4e6c0263dcdfc8c6dbb4fdd9213f5ec85fc47ae5df

Canonical: https://y2.dev/cve/CVE-2023-6918

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