CVE-2026-88920: Apache WSS4J · SAML Sender-Vouches Authentication Bypass
Affects Apache WSS4JSource CVE Database V5
Not known to be exploited · CVSS 9.8 Critical · fixed in 4.0.2 : patch Apache WSS4J as a priority.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 47% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers can reliably automate steps 1–4 of the kill chain
- Technical impact
- Total control over the software or total information disclosure
CISA SSVC assessment, 2026-09-30.
- Patch
- Available – fixed in 4.0.2, 3.0.6, 2.4.4
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 30 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade Apache to 4.0.2, 3.0.6 or 2.4.4.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Apache Software FoundationApache WSS4J | Affected
| Fixed in
|
| Apache Software FoundationApache WSS4J | Affected
| Fixed in
|
| Apache Software FoundationApache WSS4J | Affected
| Fixed in
|
MavenApache Software Foundation/org.apache.wss4j:wss4j-ws-security-dompkg:maven/Apache Software Foundation/org.apache.wss4j:wss4j-ws-security-domOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Users should upgrade Apache WSS4J to versions 4.0.2, 3.0.6, or 2.4.4 to remediate this vulnerability. No other mitigation is indicated by the vendor advisory.
Description
CVE-2026-88920 is a critical authentication bypass vulnerability in Apache WSS4J affecting the DOM security processor. It allows unauthenticated remote attackers to forge authenticated SOAP messages by using a crafted unsigned SAML sender-vouches assertion with an attacker-controlled key. This flaw enables attackers to impersonate legitimate users or services. Fixed versions are 4.0.2, 3.0.6, and 2.4.4.