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CVE-2026-88920

Apache WSS4J: SAML Sender-Vouches Authentication Bypass

Apache Software Foundation Apache WSS4J
Open in ThreatlineRecord JSON
CVSS
9.8Critical
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.57%Chance of exploitation activity in the next 30 days, higher than 46% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in4.0.2Also 3.0.6, 2.4.4CVE List
Published30 Sep 2026Updated 30 Sep 2026CVE List

What fixes it

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

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.

Text from CVE List

Affected versions 3

  • Apache WSS4Jaffected: 4.0.0 before 4.0.2CVE List
  • Apache WSS4Jaffected: 3.0.0 before 3.0.6CVE List
  • Apache WSS4Jaffected: all versions before 2.4.4CVE List

References 1