CVE-2025-5372

Libssh: 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.

Remediation

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.

Category

5.0
CVSS
Severity: Medium
CVSS 3.1 •
EPSS 0.04%
Affected: Red Hat Red Hat Enterprise Linux 10
Affected: Red Hat Red Hat Enterprise Linux 6
Affected: Red Hat Red Hat Enterprise Linux 7
Affected: Red Hat Red Hat Enterprise Linux 8
Affected: Red Hat Red Hat Enterprise Linux 9
Affected: Red Hat Red Hat OpenShift Container Platform 4
Published at:
Updated at:

References

Link Tags
https://access.redhat.com/security/cve/CVE-2025-5372 vdb entry
https://bugzilla.redhat.com/show_bug.cgi?id=2369388 issue tracking

Frequently Asked Questions

What is the severity of CVE-2025-5372?
CVE-2025-5372 has been scored as a medium severity vulnerability.
How to fix CVE-2025-5372?
As a workaround for remediating CVE-2025-5372: 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.
Is CVE-2025-5372 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2025-5372 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2025-5372?
CVE-2025-5372 affects Red Hat Red Hat Enterprise Linux 10, Red Hat Red Hat Enterprise Linux 6, Red Hat Red Hat Enterprise Linux 7, Red Hat Red Hat Enterprise Linux 8, Red Hat Red Hat Enterprise Linux 9, Red Hat Red Hat OpenShift Container Platform 4.
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