CVE-2026-19429: Jenkins Project Jenkins - Unauthorized Access to Sensitive Files

Jenkins FilePath.untarFrom() in all versions, including those with the CVE-2026-33001 patch applied, validates symlink destinations but not targets. The CVE-2026-33001 fix enforces that the symlink file is created within the workspace boundary, but the symlink target — the path returned by te.getLinkName() and passed directly to symlinkTo() — is never validated and may point to any path on the controller filesystem. An attacker with Item/Configure permission can configure a job to extract a malicious .tar or .tar.gz archive via a tool installer or custom build step. When FilePath.untarFrom() processes the archive, it creates symlinks inside the workspace that resolve to arbitrary controller paths. By targeting the entire $JENKINS_HOME/secrets/ directory — including master.key, hudson.util.Secret, hudson.model.Secrets.xml, and any other files present — an attacker can exfiltrate all Jenkins cryptographic material through the workspace viewer (GET /job/{name}/ws/) or build artifacts. Combined with credentials.xml and per-user config.xml files, this enables offline AES-128 decryption of all {AQA...}-format credential entries, exposing in plaintext every password, API key, cloud provider secret, and SSH private key stored in the Jenkins credential store — compromising all downstream systems those credentials protect.

CWE-59 Link Following