Out-of-bounds Write Affecting libssh package, versions <0.9.8-0+deb11u2


Severity

Recommended
0.0
medium
0
10

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Threat Intelligence

EPSS
0.2% (10th percentile)

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  • Snyk IDSNYK-DEBIAN11-LIBSSH-10498784
  • published25 Jun 2025
  • disclosed20 Aug 2025

Introduced: 25 Jun 2025

CVE-2025-4877  (opens in a new tab)
CWE-787  (opens in a new tab)

How to fix?

Upgrade Debian:11 libssh to version 0.9.8-0+deb11u2 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 Debian. See How to fix? for Debian:11 relevant fixed versions and status.

There's a vulnerability in the libssh package where when a libssh consumer passes in an unexpectedly large input buffer to ssh_get_fingerprint_hash() function. In such cases the bin_to_base64() function can experience an integer overflow leading to a memory under allocation, when that happens it's possible that the program perform out of bounds write leading to a heap corruption. This issue affects only 32-bits builds of libssh.

CVSS Base Scores

version 3.1