# CVE-2026-87830: Apache WSS4J: Streaming WS-SecurityPolicy validation may skip element-protection checks.

> Remote attackers can bypass WS-SecurityPolicy signature and encryption checks on SOAP elements due to flawed XPath validation in Apache WSS4J.

- **Severity:** Critical 9.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 30 Sep 2026
- **Updated:** 30 Sep 2026
- **Also known as:** DEBIAN-CVE-2026-87830, GHSA-66vg-36xv-j6x4, UBUNTU-CVE-2026-87830

## What is CVE-2026-87830?

CVE-2026-87830 is a critical vulnerability in Apache WSS4J, published on 30 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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.

Weakness: CWE-917 (Improper Neutralization of Special Elements used in an Expression Language Statement)

## Which versions are affected by CVE-2026-87830?

It affects 1 product.


Products: Apache Wss4j.

## How do I fix CVE-2026-87830?

No fix has been published for CVE-2026-87830 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-87830 being exploited?

There is no known exploitation of CVE-2026-87830 in the wild and no public exploit code.

## Other vulnerabilities in Apache WSS4J

- [CVE-2026-88920](https://insights.sbomify.com/CVE-2026-88920/): Apache WSS4J: SAML Sender-Vouches Authentication Bypass (critical 9.8)
- [CVE-2026-89238](https://insights.sbomify.com/CVE-2026-89238/): Apache WSS4J: WSS4J EncryptedHeader child confusion causing wrong protected-header selection (critical 9.1)
- [CVE-2026-85532](https://insights.sbomify.com/CVE-2026-85532/): Apache WSS4J: Insufficient Validation of Derived-Key Parameters (high 7.5)
- [CVE-2026-92121](https://insights.sbomify.com/CVE-2026-92121/): Apache WSS4J: WS-SecurityPolicy signature checks skipped in the streaming code after an STR-Transform reference (high 7.5)
- [CVE-2026-95616](https://insights.sbomify.com/CVE-2026-95616/): Apache WSS4J: Unauthenticated denial of service via integer overflow in DER parsing of X.509 certificate extensions (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-87830 and fix it if it is affected.

What it is: CVE-2026-87830 is a critical vulnerability in Apache WSS4J, published on 30 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-87830 in the wild and no public exploit code.

Affected product: Apache WSS4J. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-87830/ (Markdown: https://insights.sbomify.com/CVE-2026-87830/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-87830
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-87830
- OSV: https://osv.dev/vulnerability/CVE-2026-87830

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-87830/
Summaries are generated and may contain mistakes; the official description above is the record.