XML external entity vulnerability in Jenkins Nuget Plugin

CRITICAL 9.1CVE-2021-21658 · GHSA-p674-hh8x-rv5h · Published 25/05/2021 · updated 17/06/2026

In short

CVE-2021-21658 is a CRITICAL (CVSS 9.1) vulnerability affecting org.jenkins-ci.plugins:nuget, nuget (jenkins).
Chance of exploitation in the next 30 days (EPSS): 1.5%, higher than 74.9% of all vulnerabilities.
Fix: update to 1.1 or later.

Package	Affected versions	Patched versions
org.jenkins-ci.plugins:nuget Maven	`< 1.1`	`1.1`
nuget jenkins	`≤ 1.0`	No fix yet

Description

Jenkins Nuget Plugin 1.0 and earlier does not configure its XML parser to prevent XML external entity (XXE) attacks. This XML parser is used for the "Build on NuGet updates" feature.

This allows attackers with the ability to control the contents of the packages.config file in a workspace to have Jenkins parse a crafted XML document that uses external entities for extraction of secrets from the Jenkins controller or server-side request forgery.

Jenkins Nuget Plugin 1.1 disables external entity resolution for its XML parser.

NVD description

Jenkins Nuget Plugin 1.0 and earlier does not configure its XML parser to prevent XML external entity (XXE) attacks.

References

nvd.nist.gov/vuln/detail/CVE-2021-21658 · ADVISORY
jenkinsci/nuget-plugin commit 542bf38 · WEB
jenkinsci/nuget-plugin commit c8ed4cb · WEB
jenkinsci/nuget-plugin · PACKAGE
jenkins.io/security/advisory/2021-05-25 · WEB
openwall.com/lists/oss-security/2021/05/25/3 · WEB

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