Is CVE-2026-84657 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-84657 being exploited in the wild.

How severe is CVE-2026-84657?

Medium severity, with a CVSS score of 4.2, 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-2026-84657?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-84657 attacked?

It is attacked over the network, in a web application.

Am I affected by CVE-2026-84657?

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.

CVE-2026-84657: Jenkins build CLI command authorization bypass via -s flag

CVE-2026-84657 · Severity: medium · CVSS 4.2 · Published 2026-09-02

Jenkins is an open-source automation server widely used for continuous integration and deployment. The build CLI command has an authorization flaw that allows users with permission to trigger builds to cancel builds initiated by other users, even if they lack explicit cancellation authority. This could disrupt production deployments, interrupt critical automation tasks, or cause denial-of-service impacts on shared CI/CD infrastructure.

Technologies: Jenkins. Vendors: Jenkins.

Quick answers

Is CVE-2026-84657 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-84657 being exploited in the wild.
How severe is CVE-2026-84657?: Medium severity, with a CVSS score of 4.2, 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-2026-84657?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-84657 attacked?: It is attacked over the network, in a web application.
Am I affected by CVE-2026-84657?: 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

The build CLI command in Jenkins fails to enforce the Item/Cancel permission check when the -s flag (synchronous/wait for completion) is used to cancel a running build. An attacker with Item/Build permission can invoke the build command with -s and use it to cancel any active build, not just their own. The vulnerability exists in Jenkins 2.579 and earlier, and LTS 2.568.2 and earlier. The fix is included in Jenkins 2.580 and LTS 2.568.3, which properly validate the Item/Cancel permission before allowing build cancellation via CLI.

Affected products

Jenkins Jenkins 2.579 and earlier, LTS 2.568.2 and earlier

Timeline

2026-09-02: disclosed

References

https://www.jenkins.io/security/advisory/2026-09-02/

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