Due to a time-of-check to time-of-use (TOCTOU) race condition, the file browser for workspaces, archived artifacts, and $JENKINS_HOME/userContent/ follows symbolic links to locations outside the directory being browsed in Jenkins 2.275 and LTS 2.263.2. This allows attackers with Job/Workspace permission and the ability to control workspace contents, e.g., with Job/Configure permission or the ability to change SCM contents, to create symbolic links that allow them to access files outside workspaces using the workspace browser. Jenkins 2.276, LTS 2.263.3 no longer differentiates the check and the use of symlinks in workspace browsers. Note: This issue is caused by an incorrectly applied fix for CVE-2021-21602.
Due to a time-of-check to time-of-use (TOCTOU) race condition, the file browser for workspaces, archived artifacts, and $JENKINS_HOME/userContent/ follows symbolic links to locations outside the directory being browsed in Jenkins 2.275 and LTS 2.263.2. This allows attackers with Job/Workspace permission and the ability to control workspace contents, e.g., with Job/Configure permission or the ability to change SCM contents, to create symbolic links that allow them to access files outside workspaces using the workspace browser. Jenkins 2.276, LTS 2.263.3 no longer differentiates the check and the use of symlinks in workspace browsers. Note: This issue is caused by an incorrectly applied fix for CVE-2021-21602.
https://www.jenkins.io/security/advisory/2021-01-26/#SECURITY-2197 https://issues.jenkins.io/browse/JENKINS-64632 https://github.com/jenkinsci/jenkins/pull/5188 https://github.com/jenkinsci/jenkins/commit/f2d289c00153d71ae5400b2986469b162d1dc6ce
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