# CVE-2026-57303: Jenkins Assembla Plugin has an XXE vulnerability

> Attackers controlling Assembla server responses can exploit XXE to extract Jenkins secrets or perform SSRF.

- **Severity:** High 7.1 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 24 Jun 2026
- **Updated:** 24 Jun 2026
- **Also known as:** GHSA-2q27-6p2h-q6r3

## What is CVE-2026-57303?

CVE-2026-57303 is a high-severity vulnerability in Jenkins Assembla Plugin, published on 24 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Jenkins Assembla Plugin 1.4 and earlier does not configure its XML parser to prevent XML external entity (XXE) attacks, allowing attackers able to control the responses of the configured Assembla server to extract secrets from the Jenkins controller or perform server-side request forgery.

Weakness: CWE-918 (Server-Side Request Forgery)

## Which versions are affected by CVE-2026-57303?

2 open source packages ship an affected version, including org.jenkins-ci.plugins:assembla. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `org.jenkins-ci.plugins:assembla` | Maven | All versions to 1.4 | None |
| `org.jenkins-ci.plugins:assembla` | Maven | All versions to 1.4 | None |

Products: Jenkins Assembla.

## How do I fix CVE-2026-57303?

No fix has been published for CVE-2026-57303 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-57303 being exploited?

There is no known exploitation of CVE-2026-57303 in the wild and no public exploit code.

## Other vulnerabilities in Jenkins Assembla Plugin

- [CVE-2023-37961](https://insights.sbomify.com/CVE-2023-37961/): Jenkins Assembla Auth Plugin vulnerable to cross-site request forgery (high 8.8)
- [CVE-2019-10420](https://insights.sbomify.com/CVE-2019-10420/): Jenkins Assembla Plugin has Insufficiently Protected Credentials (medium 5.5)
- [CVE-2026-57304](https://insights.sbomify.com/CVE-2026-57304/): Jenkins Assembla Plugin has a missing permission check (medium 5.4)
- [CVE-2026-57305](https://insights.sbomify.com/CVE-2026-57305/): Jenkins Assembla Plugin has a cross-site request forgery (CSRF) vulnerability (medium 5.4)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-57303 and fix it if it is affected.

What it is: CVE-2026-57303 is a high-severity vulnerability in Jenkins Assembla Plugin, published on 24 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-57303 in the wild and no public exploit code.

Affected packages and fixed versions:
- org.jenkins-ci.plugins:assembla (Maven): affected all versions up to 1.4; no fix listed
- org.jenkins-ci.plugins:assembla (Maven): affected all versions up to 1.4; no fix listed

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-2026-57303/ (Markdown: https://insights.sbomify.com/CVE-2026-57303/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-57303
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-57303
- OSV: https://osv.dev/vulnerability/CVE-2026-57303

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-57303/
Summaries are generated and may contain mistakes; the official description above is the record.