# CVE-2026-84656: Jenkins missing permission check on build parameters

Source: https://junglewise.ai/threats/cve-2026-84656-jenkins-missing-permission-check-on-build-parameters  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-02. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-84656 · Severity: medium · CVSS 4.3 · Published 2026-09-02

Jenkins, a widely-used automation and CI/CD server, contains a permission bypass flaw that allows attackers with limited access (Item/Read on one job) to read sensitive build parameter names and values from jobs they should not have access to. Build parameters often contain secrets such as API keys, passwords, and deployment credentials, making this exposure a risk to operational security and compliance.

Technologies: [Jenkins](https://junglewise.ai/threats/technologies/jenkins). Vendors: [Jenkins](https://junglewise.ai/threats/vendors/jenkins).

## Quick answers

**Is CVE-2026-84656 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-84656 being exploited in the wild.

**How severe is CVE-2026-84656?** Medium severity, with a CVSS score of 4.3, published 2 September 2026.

**Which products and versions are affected?** Jenkins 2.579 and earlier, LTS 2.568.2 and earlier.

**Is there a fix for CVE-2026-84656?** A patch was published on 2026-09-02: Jenkins 2.580, LTS 2.568.3 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-84656 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-84656?** Check whether you run Jenkins at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

Jenkins 2.579 and earlier (LTS 2.568.2 and earlier) fails to properly validate permissions when exposing build parameter metadata. An attacker with Item/Read permission on at least one job can leverage this missing permission check to enumerate and read parameter names and values from jobs outside their authorization scope. The vulnerability is network-accessible and does not require authentication beyond the minimum Item/Read permission already held on one accessible job. Exploitation could expose API keys, passwords, and other sensitive configuration data stored in build parameters. Jenkins 2.580 and LTS 2.568.3 include a fix restricting parameter access based on proper job-level authorization checks.

## Affected products

- Jenkins Jenkins 2.579 and earlier, LTS 2.568.2 and earlier

## Timeline

- 2026-09-02: disclosed
- 2026-09-02: patched: Jenkins 2.580, LTS 2.568.3

## References

- [https://www.jenkins.io/security/advisory/2026-09-02/](https://www.jenkins.io/security/advisory/2026-09-02/)

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