High severity · published Mar 12, 2026
CVE-2026-3099
Libsoup: libsoup: authentication bypass via digest authentication replay attack
7.3
CVSS
0.4%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
Low
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 30% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
RH
Red Hat Enterprise Linux 6 · Red Hat
All versions, or not specified · source: vendor
EL
Enterprise Linux · Redhat
6.0; 7.0; 8.0; 9.0; 10.0 · source: NVD
LI
Libsoup · Gnome
All versions, or not specified · source: NVD
Affected product
RH
Red Hat Enterprise Linux 6
Red Hat
More from Red Hat Enterprise Linux 6
8.8
CVE-2025-31277
Apple Multiple Products Buffer Overflow Vulnerability
7.5
CVE-2026-34486
Apache Tomcat: Fix for CVE-2026-29146 allowed bypass of EncryptInterceptor
10.0
CVE-2026-4692
Sandbox escape in the Responsive Design Mode component
10.0
CVE-2026-4689
Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component
10.0
CVE-2026-4688
Sandbox escape due to use-after-free in the Disability Access APIs component