CVE-2026-88920: wss4j Auth Bypass — Fix

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.

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CVSS v3.1 Score

9.8

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0057

Probability of exploitation

0.46%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-287 Improper Authentication

Affected Products

Vendor	Product	Versions
apache	wss4j	< 2.4.4
apache	wss4j	3.0.0 — 3.0.6
apache	wss4j	4.0.0 — 4.0.2

References

Advisories & Patches

https://lists.apache.org/thread.html/grt43m3bgbzz0mk0cnho3rcybb1j01z9

Other References

http://www.openwall.com/lists/oss-security/2026/09/30/10

Frequently Asked Questions

What is CVE-2026-88920? +

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. It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2026-88920? +

CVE-2026-88920 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0057, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-88920? +

CVE-2026-88920 affects products from apache, specifically: wss4j. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-88920? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2026-88920