# CVE-2026-15554: Undertow-core: undertow: authentication bypass via ajp ssl_cert/is_ssl forgery

> An unauthenticated attacker can bypass CLIENT-CERT authentication in Undertow AJP by forging SSL attributes, requiring network access to port 8009.

- **Severity:** High 7.4 (`CVSS:3.1/AV:N/AC:H/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:** Yes
- **Published:** 11 Aug 2026
- **Updated:** 20 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-15554, GHSA-f478-cwfc-jqh3, UBUNTU-CVE-2026-15554

## What is CVE-2026-15554?

CVE-2026-15554 is a high-severity authentication bypass vulnerability in Red Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 7, published on 11 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

the Undertow AJP listener honours forged ssl_cert and is_ssl AJP attributes without requiring any shared-secret authentication. This enables an unauthenticated attacker with direct TCP access to port 8009 to bypass CLIENT-CERT authentication by injecting a forged X.509 certificate via the AJP protocol.

Weakness: CWE-295 (Improper Certificate Validation)

## Which versions are affected by CVE-2026-15554?


## How do I fix CVE-2026-15554?

Apply the vendor's patch.

## Is CVE-2026-15554 being exploited?

There is no known exploitation of CVE-2026-15554 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-15554 and fix it if it is affected.

What it is: CVE-2026-15554 is a high-severity authentication bypass vulnerability in Red Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 7, published on 11 Aug 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-2026-15554 in the wild and no public exploit code.

Affected product: Red Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 7. 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-2026-15554/ (Markdown: https://insights.sbomify.com/CVE-2026-15554/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-15554
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-15554
- OSV: https://osv.dev/vulnerability/CVE-2026-15554

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-15554/
Summaries are generated and may contain mistakes; the official description above is the record.