CVE-2021-21689: Jenkins Security Advisory 2021-11-04

Lack of email address ownership verification in the CODEOWNERS feature in all versions of GitLab EE since version 11.3 allows an attacker to bypass CODEOWNERS Merge Request approval requirement under rare circumstances

Jenkins 2.318 and earlier, LTS 2.303.2 and earlier does not check agent-to-controller access to create symbolic links when unarchiving a symbolic link in FilePath#untar.

Jenkins 2.318 and earlier, LTS 2.303.2 and earlier does not check agent-to-controller access to create parent directories in FilePath#mkdirs.

File path filters in the agent-to-controller security subsystem of Jenkins 2.318 and earlier, LTS 2.303.2 and earlier do not canonicalize paths, allowing operations to follow symbolic links to outside allowed directories.

Jenkins 2.318 and earlier, LTS 2.303.2 and earlier allows any agent to read and write the contents of any build directory stored in Jenkins with very few restrictions.

FilePath#renameTo and FilePath#moveAllChildrenTo in Jenkins 2.318 and earlier, LTS 2.303.2 and earlier only check 'read' agent-to-controller access permission on the source path, instead of 'delete'.

When creating temporary files, agent-to-controller access to create those files is only checked after they've been created in Jenkins 2.318 and earlier, LTS 2.303.2 and earlier.

FilePath#listFiles lists files outside directories that agents are allowed to access when following symbolic links in Jenkins 2.318 and earlier, LTS 2.303.2 and earlier.

FilePath#toURI, FilePath#hasSymlink, FilePath#absolutize, FilePath#isDescendant, and FilePath#get*DiskSpace do not check any permissions in Jenkins 2.318 and earlier, LTS 2.303.2 and earlier.

Creating symbolic links is possible without the 'symlink' agent-to-controller access control permission in Jenkins 2.318 and earlier, LTS 2.303.2 and earlier.