CVE-2021-21615 log

Source
Severity Medium
Remote Yes
Type Directory traversal
Description
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.
Group Package Affected Fixed Severity Status Ticket
AVG-1491 jenkins 2.275-1 2.276-1 Medium Fixed
References
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