CVE-2026-27598: Dagu: Path traversal in DAG creation allows arbitrary YAML file write outside DAGs directory

Vulnerability summary

CVE-2026-27598 is a high (CVSS 7.1) vulnerability in dagu-org dagu. EPSS estimates a 0.65% chance of exploitation in the next 30 days, higher than 51.1% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 25-02-2026
   PublishedVulnerability first disclosed.
2. 26-02-2026
   Last modifiedVulnerability information updated.

Description

Dagu is a workflow engine with a built-in Web user interface. In versions up to and including 1.16.7, the `CreateNewDAG` API endpoint (`POST /api/v1/dags`) does not validate the DAG name before passing it to the file store. An authenticated user with DAG write permissions can write arbitrary YAML files anywhere on the filesystem (limited by the process permissions). Since dagu executes DAG files as shell commands, writing a malicious DAG to the DAGs directory of another instance or overwriting config files can lead to remote code execution. Commit e2ed589105d79273e4e6ac8eb31525f765bb3ce4 fixes the issue.

• CWE-22Improper Limitation of a Pathname to a Restricted DirectoryThe product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.