Apache WSS4J: Protection Mechanism Failure
CVE-2026-92121 is a high-severity protection mechanism failure vulnerability in Apache WSS4J from Apache, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 4.0.2, 3.0.6, 2.4.4 as the first without the flaw, so updating Apache WSS4J to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.55% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Apache WSS4J to 4.0.2 or 3.0.6 or 2.4.4, whichever matches your release line, or a later version.
- Update Wss4j to 2.4.4 or 3.0.6 or 4.0.2, whichever matches your release line, or a later version.
- Read the advisory on lists.apache.org for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Apache | Apache WSS4J | 4.0.0 up to, but not including, 4.0.2; 3.0.0 up to, but not including, 3.0.6; before 2.4.4 | 4.0.2, 3.0.6, 2.4.4 |
| Apache | Wss4j | before 2.4.4; 3.0.0 up to, but not including, 3.0.6; 4.0.0 up to, but not including, 4.0.2 | 2.4.4, 3.0.6, 4.0.2 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N. Scored by CISA (ADP).
Official description
In the WSS4J streaming (StAX) code, a signature reference using the WS-Security STR-Transform leaves an internal "inside signed content" flag permanently set. The WS-SecurityPolicy enforcer uses that flag to decide whether an element needs checking, so it stops evaluating SignedParts and SignedElements for the rest of the message. A policy requiring the SOAP Body to be signed is then satisfied even when the Body carries no signature, removing the protection against XML Signature Wrapping. Signature verification itself is unaffected. The DOM code is not affected. Users are recommended to upgrade to versions 4.0.2 or 3.0.6 or 2.4.4 which fix this issue.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Protection Mechanism Failure
The product does not use or incorrectly uses a protection mechanism that provides sufficient defense against directed attacks against the product.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- openwall.com/lists/oss-security/2026/09/30/12Mailing List, Third Party Advisory
Other vulnerabilities in Apache WSS4J
- 7.5 High severity
- 9.1 Critical severity
- 9.8 Critical severity
- 9.1 Critical severity
- 7.5 High severity
Recent Protection Mechanism Failure vulnerabilities
- 9.6 Critical severity
- 9.6 Critical severity
- 8.8 High severity
- 9.6 Critical severity
- 9.6 Critical severity
- 8.2 High severity
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