---
id: CVE-2026-59847
title: A flaw was found in libssh
summary: >-
  A flaw was found in libssh. Incorrect AES-GCM finalization checks in builds
  using the OpenSSL backend can effectively remove integrity protection,
  allowing an in-path attacker to modify plaintext on the wire without
  detection.
severity: medium
cvss: 5.9
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N'
cwe:
  - CWE-253
  - CWE-1310
vendor: libssh
product: libssh
affected:
  - 'libssh >= 0.9.0, < 0.11.5'
  - libssh = 0.12.0
  - hardened_images
  - enterprise_linux = 8.0
  - enterprise_linux = 9.0
  - enterprise_linux = 10.0
patched:
  - libssh 0.11.5
published: '2026-07-21'
updated: '2026-09-04'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-59847'
references:
  - url: 'https://access.redhat.com/errata/RHSA-2026:42922'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:55855'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:62217'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:62218'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/security/cve/CVE-2026-59847'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2498180'
    label: secalert@redhat.com
tags:
  - nvd
epss: 0.00568
epssPercentile: 0.44745
ingestedAt: '2026-09-05T13:39:55.795Z'
---

## Overview

A flaw was found in libssh. Incorrect AES-GCM finalization checks in builds using the OpenSSL backend can effectively remove integrity protection, allowing an in-path attacker to modify plaintext on the wire without detection.

## Affected

- `libssh >= 0.9.0, < 0.11.5`
- `libssh = 0.12.0`
- `hardened_images`
- `enterprise_linux = 8.0`
- `enterprise_linux = 9.0`
- `enterprise_linux = 10.0`

## Remediation

Upgrade past the affected range:

- `libssh 0.11.5`