Incorrect Calculation Affecting libssh package, versions <0.9.6-2ubuntu0.22.04.4


Severity

Recommended
medium

Based on Ubuntu security rating.

Threat Intelligence

EPSS
0.05% (15th percentile)

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  • Snyk IDSNYK-UBUNTU2204-LIBSSH-10500575
  • published8 Jul 2025
  • disclosed4 Jul 2025

Introduced: 4 Jul 2025

CVE-2025-5372  (opens in a new tab)
CWE-682  (opens in a new tab)

How to fix?

Upgrade Ubuntu:22.04 libssh to version 0.9.6-2ubuntu0.22.04.4 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream libssh package and not the libssh package as distributed by Ubuntu. See How to fix? for Ubuntu:22.04 relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1