CVE-2026-88920 Apache WSS4J: SAML Sender-Vouches Authentication Bypass

What is CVE-2026-88920?

CVE-2026-88920 is a critical authentication bypass vulnerability in Apache WSS4J, published on 30 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

An authentication bypass in the DOM security processor in Apache WSS4J allows unauthenticated remote attackers to forge authenticated SOAP messages via a crafted unsigned SAML sender-vouches assertion containing an attacker-controlled key.

Users are recommended to upgrade to versions 4.0.2 or 3.0.6 or 2.4.4, which fix this issue.

Weakness: CWE-287

Which versions are affected by CVE-2026-88920?

It affects 1 product.

Products include Apache Wss4j.

How do I fix CVE-2026-88920?

No fix has been published for CVE-2026-88920 yet. Limit exposure of the affected software until one is available.

Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.

Is CVE-2026-88920 being exploited?

There is no known exploitation of CVE-2026-88920 in the wild and no public exploit code.

Other vulnerabilities in Apache WSS4J

• CVE-2026-87830 Apache WSS4J: Streaming WS-SecurityPolicy validation may skip element-protection checks. Critical 9.1
• CVE-2026-89238 Apache WSS4J: WSS4J EncryptedHeader child confusion causing wrong protected-header selection Critical 9.1
• CVE-2026-85532 Apache WSS4J: Insufficient Validation of Derived-Key Parameters High 7.5
• CVE-2026-92121 Apache WSS4J: WS-SecurityPolicy signature checks skipped in the streaming code after an STR-Transform reference High 7.5
• CVE-2026-95616 Apache WSS4J: Unauthenticated denial of service via integer overflow in DER parsing of X.509 certificate extensions High 7.5

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2026-88920, GHSA-4c9g-74h5-78r7, UBUNTU-CVE-2026-88920.