Apache WSS4J Replay Attack via Nonce Replay Cache (v4.0.2/3.0.6/2.4.4)
CVE-2026-92899 Published on September 30, 2026
Apache WSS4J: UsernameToken replay protection bypassed by re-encoding the Nonce
Apache WSS4J remembers the Nonce of each UsernameToken it accepts, so a captured token cannot be reused. It stored the Nonce as raw base64 text, but authentication decodes that text and uses the bytes.The same bytes can be written as base64 in several ways. An attacker who captured an authenticated request could re-send it with a space added to the Nonce: the password digest still verified, but the token no longer matched the remembered one, so the replay was accepted. Since a UsernameToken does not cover the message body, the captured token could then be reused on requests of the attacker's choosing until it expired. Affects deployments with a nonce replay cache configured, as Apache CXF has by default, and only tokens using a password digest. The cache is now keyed on the decoded Nonce. Users are recommended to upgrade to versions 4.0.2 or 3.0.6 or 2.4.4, which fix this issue.
Vulnerability Analysis
CVE-2026-92899 can be exploited with network access, and does not require authorization privileges or 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 have a small impact on confidentiality and integrity, and no impact on availability.
Weakness Type
Authentication Bypass by Spoofing
This attack-focused weakness is caused by improperly implemented authentication schemes that are subject to spoofing attacks.
Products Associated with CVE-2026-92899
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Affected Versions
Apache Software Foundation Apache WSS4J:- Version 4.0.0 and below 4.0.2 is affected.
- Version 3.0.0 and below 3.0.6 is affected.
- Before 2.4.4 is affected.