CVE-2026-3099
This vulnerability allows a remote attacker to capture a single valid authentication header and replay it repeatedly.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.36%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public 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.
- CVSS 3.1
- 7.3 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
- EPSS
- 0.36% probability · 29th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-323
- Affected
- gnome/libsoup · redhat/enterprise linux
- Source
- secalert@redhat.com
References
- https://access.redhat.com/security/cve/CVE-2026-3099Third Party Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2442232Issue Tracking, Third Party Advisory
- https://gitlab.gnome.org/GNOME/libsoup/-/issues/495Exploit, Issue Tracking, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.