CVE-2026-57300: Jenkins MCP Server Plugin missing permission check in Pipeline replay scripts

CVE-2026-57300 · Severity: medium · CVSS 4.3 · Published 2026-06-24

The Jenkins MCP Server Plugin, which facilitates communication between Jenkins and Model Context Protocol servers, contains a security flaw where it fails to properly verify user permissions. This allows an authorized Jenkins user who has basic read access to a project to view sensitive Pipeline replay scripts that they should not be able to see. This could lead to the exposure of proprietary build logic or sensitive information contained within those scripts.

Vendors: Jenkins Project, Maven.

Quick answers

Is CVE-2026-57300 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-57300 being exploited in the wild.
How severe is CVE-2026-57300?
Medium severity, with a CVSS score of 4.3, published 24 June 2026.
Which products and versions are affected?
Jenkins Project MCP Server Plugin 0.177.v629fdb_2557fe and earlier; io.jenkins.plugins:mcp-server (Maven) < 0.178.vffe5a, ECOSYSTEM:introduced=0,fixed=0.178.vffe5a.
Is there a fix for CVE-2026-57300?
Yes. io.jenkins.plugins:mcp-server (Maven): upgrade to 0.178.vffe5a or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-57300 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-57300?
Check whether you run Jenkins Project MCP Server Plugin or io.jenkins.plugins:mcp-server (Maven) 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.

How to fix

  • io.jenkins.plugins:mcp-server (Maven): upgrade to 0.178.vffe5a or later
    # set io.jenkins.plugins:mcp-server to 0.178.vffe5a in your pom.xml or build.gradle

Technical details

A missing permission check vulnerability exists in the Jenkins MCP Server Plugin versions 0.177.v629fdb_2557fe and earlier. The vulnerability is located in the component responsible for handling Pipeline replay scripts. An attacker with 'Item/Read' permission can bypass intended access controls to read the content of replay scripts for any job they have read access to, even if they lack the higher-level permissions normally required to view such scripts. This occurs because the plugin does not explicitly verify if the requesting user has the appropriate authorization to access the replay data. The issue is addressed in version 0.178.vffe5a_e770f3b_ and later.

Affected products

  • Jenkins Project MCP Server Plugin 0.177.v629fdb_2557fe and earlier

Identifiers

  • CVE-2026-57300
  • GHSA-mpff-xhg4-vr45

Timeline

  • 2026-06-24: disclosed
  • 2026-06-24: advisory

References

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