CVE-2026-3099

Libsoup: libsoup: authentication bypass via digest authentication replay attack

HIGH
7.3
CVSS Score
Published: March 12, 2026 at 01:53 PM UTC
Updated: June 17, 2026 at 10:43 AM UTC
2 products affected across 2 vendorsEnterprise LinuxLibsoup

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Severity
HIGH7.3
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

All versions
Vendor states this is fixed in 10 (unaffected)
Vendor states this is fixed in 7 (unaffected)
Vendor states this is fixed in 8 (unaffected)
Vendor states this is fixed in 9 (unaffected)
Vendor states this is fixed in 6 (unknown)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (3)

VDB Entryx_refsource_REDHATThird Party Advisory
Source: cverecord
https://access.redhat.com/security/cve/CVE-2026-3099
Issue Trackingx_refsource_REDHATThird Party Advisory
Source: cverecord
https://bugzilla.redhat.com/show_bug.cgi?id=2442232
ExploitIssue TrackingThird Party Advisory
Source: cverecord
https://gitlab.gnome.org/GNOME/libsoup/-/issues/495

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
LOW
Availability
LOW
Vector?

Quick Info

StatusANALYZED
CWE
CWE-323

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