---
id: CVE-2025-4877
title: >-
  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
summary: >-
  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…
severity: medium
cvss: 4.5
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L'
cwe:
  - CWE-787
published: '2025-08-20'
updated: '2026-06-25'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-4877'
references:
  - url: 'https://access.redhat.com/errata/RHSA-2026:18683'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/security/cve/CVE-2025-4877'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2376193'
    label: secalert@redhat.com
  - url: >-
      https://git.libssh.org/projects/libssh.git/commit/?h=stable-0.11&id=6fd9cc8ce3958092a1aae11f1f2e911b2747732d
    label: secalert@redhat.com
  - url: 'https://www.libssh.org/security/advisories/CVE-2025-4877.txt'
    label: secalert@redhat.com
tags:
  - nvd
epss: 0.00197
epssPercentile: 0.09684
ingestedAt: '2026-06-29T13:24:34.405Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.