This vulnerability exists in the SoupAuthDomainDigest class of Libsoup, where the server-side digest authentication fails to properly track nonces and enforce the nonce-count (nc) increment requirement. As a result, an attacker who captures a valid authentication header can replay it multiple times to bypass authentication controls. This leads to unauthorized access by impersonating legitimate users on Red Hat Enterprise Linux 10 systems. The issue is documented under CVE-2026-3099 with a medium CVSS score of 5.8, reflecting network attack vector, high attack complexity, no privileges required, user interaction required, and partial impact on confidentiality, integrity, and availability.

An attacker can replay a captured valid authentication header repeatedly to bypass authentication mechanisms, allowing unauthorized access to protected resources and impersonation of legitimate users. The impact affects confidentiality, integrity, and availability to a limited extent as indicated by the CVSS vector. There are no known exploits in the wild at this time.

The vendor advisory does not provide explicit information on patch availability or mitigation steps. Patch status is not yet confirmed — check the Red Hat advisory at https://access.redhat.com/security/cve/CVE-2026-3099 for current remediation guidance. Until a fix is confirmed, consider limiting exposure of affected services and monitoring for suspicious authentication attempts related to replay attacks.