CVE-2026-3099
libsoup: Libsoup: Authentication bypass via digest authentication replay attack
Severity
ModerateRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · February 24, 2026
Updated · July 9, 2026
Description
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.
Statement
This issue was rated as having a moderate impact. A flaw exists in Libsoup's server-side digest authentication, which does not properly track nonces or enforce incrementing nonce-counts. This allows an attacker to replay captured authentication headers, bypassing authentication and gaining unauthorized access to protected resources.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
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.
CVSS / CWE
CVSS 3.1 · 5.8CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:L
CWE-323 · Reusing a Nonce, Key Pair in Encryption