Libsoup Digest Auth Replay Vulnerability (nonce & nc tracking)
CVE-2026-3099 Published on March 12, 2026
Libsoup: libsoup: authentication bypass via digest authentication replay attack
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.
Vulnerability Analysis
CVE-2026-3099 can be exploited with network access, requires user interaction. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to be low. considered to have a small impact on confidentiality and integrity and availability.
Timeline
Reported to Red Hat.
Made public.
Weakness Type
Reusing a Nonce, Key Pair in Encryption
Nonces should be used for the present occasion and only once.
Products Associated with CVE-2026-3099
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