Cyber Resilience

CVE-2023-6918

Libssh 0.9.0 – 0.9.8

Published
19 December 2023
Modified
15 February 2025
Patch / advisory
View advisory
CVSS Score v3.1 3.7
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
EPSS Score 0.014 70th percentile
Risk Priority 36 floored blend · peak EPSS

Summary

CVE-2023-6918 is a low-severity Unchecked Return Value (CWE-252) vulnerability in Libssh Libssh. Its CVSS base score is 3.7 (Low).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked in the top 30% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

OWASP Top 10 for Web (2025)

A10:2025 Mishandling of Exceptional Conditions

EU & UK References

Vulnerability Data

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…

more

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.

CWE(s)
CWE-252

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
attack.mitre.org →
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-6004Same product: Fedoraproject Fedora
CVE-2023-2283Same product: Fedoraproject Fedora
CVE-2026-59850Same product: Libssh Libssh
CVE-2025-5372Same product: Libssh Libssh
CVE-2026-15370Same product: Libssh Libssh
CVE-2025-5318Same product: Libssh Libssh
CVE-2026-59842Same product: Libssh Libssh
CVE-2023-40549Same product: Fedoraproject Fedora
CVE-2023-40550Same product: Fedoraproject Fedora
CVE-2023-40551Same product: Fedoraproject Fedora

Affected Assets

libssh
libssh
0.9.0 — 0.9.8 · 0.10.0 — 0.10.6
fedoraproject
fedora
38, 39
redhat
enterprise linux
8.0, 9.0

Mitigating Controls

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require checking and handling all function return values to detect error conditions.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing in development and acceptance can detect missing return-value checks.

A.8.25 Secure development life cycle partial match
prevents

Secure development life cycle mandates verification of return values to prevent undetected failures.

A.8.26 Application security requirements partial match
prevents

Application security requirements include input/output validation and error handling that covers return-value checks.

A.8.27 Secure system architecture and engineering principles partial match
degrades

Secure system architecture and engineering principles require robust error handling and defensive coding practices.

A.8.28 Secure coding partial match
prevents

Secure coding explicitly requires checking return values to avoid CWE-252.

References