---
id: CVE-2026-87830
title: >-
  In the StAX streaming WS-SecurityPolicy validator, certain relative or
  unsupported XPath expressions can be converted into paths that never match the
  actual XML element path
summary: >-
  In the StAX streaming WS-SecurityPolicy validator, certain relative or
  unsupported XPath expressions can be converted into paths that never match the
  actual XML element path. A remote SOAP peer may therefore send a required
  element witho…
severity: critical
cvss: 9.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N'
cwe:
  - CWE-917
vendor: apache
product: wss4j
affected:
  - wss4j < 2.4.4
  - 'wss4j >= 3.0.0, < 3.0.6'
  - 'wss4j >= 4.0.0, < 4.0.2'
patched:
  - wss4j 4.0.2
published: '2026-09-30'
updated: '2026-10-06'
sourceUpdated: '2026-10-06T17:26:47.927'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-87830'
references:
  - url: 'https://lists.apache.org/thread.html/lwlozb1x20d16f9dnyvoygc9rrhzq2vn'
    label: security@apache.org
  - url: 'http://www.openwall.com/lists/oss-security/2026/09/30/9'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
  - cve.org
epss: 0.00217
epssPercentile: 0.12125
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-09-30T19:46:48.561887Z'
ingestedAt: '2026-09-30T12:02:58.585Z'
---

## Overview

In the StAX streaming WS-SecurityPolicy validator, certain relative or unsupported XPath expressions can be converted into paths that never match the actual XML element path. A remote SOAP peer may therefore send a required element without the expected signature or encryption.
Users are recommended to upgrade to versions 4.0.2 or 3.0.6 or 2.4.4, which fix this issue.

## Affected

- `wss4j < 2.4.4`
- `wss4j >= 3.0.0, < 3.0.6`
- `wss4j >= 4.0.0, < 4.0.2`

## Remediation

Upgrade past the affected range:

- `wss4j 4.0.2`