WSS4J is a widely used SOAP security library; auth bypass enables forging authenticated SAML SOAP messages across many enterprise apps and middleware.
CVE-2026-88920
Auth bypass in Apache WSS4J allows forging authenticated SAML SOAP messages.
Is CVE-2026-88920 being exploited?
Not confirmed. CVE-2026-88920 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked.
How severe is CVE-2026-88920?
CVE-2026-88920 is rated Critical with a CVSS score of 9.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-88920?
Yes. A fix has been recorded for CVE-2026-88920. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-88920 affect?
CVE-2026-88920 affects Apache WSS4J prior to 4.0.2 / 3.0.6 / 2.4.4, SOAP/SAML-enabled applications using WSS4J, Middleware and enterprise apps using WSS4J. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-88920?
Upgrade WSS4J to 4.0.2 / 3.0.6 / 2.4.4 immediately; review SAML sender-vouches handling.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Unauthenticated attacker can forge authenticated SOAP messages (SAML sender-vouches) to impersonate users, bypass access controls and invoke privileged web service actions.
Immediate action required
- affected>= 4.0.0 and < 4.0.2
- affected>= 3.0.0 and < 3.0.6
- affected< 2.4.4
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.