---
id: CVE-2026-3099
title: >-
  Libsoup: libsoup: authentication bypass via digest authentication replay
  attack
summary: >-
  A flaw was found in Libsoup. The server-side digest authentication
  implementation in the SoupAuthDomainDigest class does not properly track
  issued nonces or enforce the required incrementing nonce-count (nc) attribute.
  This vulnerability…
severity: medium
cvss: 5.8
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:L'
cvssSource: cna
cwe:
  - CWE-323
vendor: Red Hat
product: libsoup3
affected:
  - libsoup3
  - libsoup
  - libsoup
  - libsoup
  - libsoup
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-03-12T17:44:33.434069Z'
published: '2026-03-12'
updated: '2026-11-05'
sourceUpdated: '2026-11-05T20:09:28.308Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-3099'
references:
  - url: 'https://access.redhat.com/security/cve/CVE-2026-3099'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2442232'
    label: RHBZ#2442232
  - url: 'https://gitlab.gnome.org/GNOME/libsoup/-/issues/495'
tags:
  - cve.org
epss: 0.00369
epssPercentile: 0.30945
ingestedAt: '2026-11-05T22:38:31.696Z'
---

## Overview

A flaw was found in Libsoup. The server-side digest authentication implementation in the SoupAuthDomainDigest class does not properly track issued nonces or enforce the required incrementing nonce-count (nc) attribute. This vulnerability allows a remote attacker to capture a single valid authentication header and replay it repeatedly. Consequently, the attacker can bypass authentication and gain unauthorized access to protected resources, impersonating the legitimate user.

## Affected

- `libsoup3`
- `libsoup`
- `libsoup`
- `libsoup`
- `libsoup`

## Remediation

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

### Workarounds

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.