CVE-2026-58370: Woodpecker < 3.15.0 - GitLab Approval Gate Bypass via Spoofable Commit Author Name

Synopsis

This is an authentication bypass vulnerability in Woodpecker CI's GitLab forge driver affecting versions before 3.15.0. It is reachable over the network without any credentials, because the bypass exploits attacker-controlled data in a GitLab webhook payload rather than requiring a valid account on the Woodpecker instance itself. Successful exploitation lets an attacker run arbitrary pipeline steps on a Woodpecker agent and exfiltrate any CI secrets exposed to that pipeline run. A patched-image rebuild at version 3.15.0 is available on HarborGuard for environments running an affected version.

HarborGuard Coverage

Exploit Conditions

• Network reachabilityRequired

  The attacker must be able to reach the Woodpecker instance over the network by submitting a merge request from a fork, which causes GitLab to send a webhook with the crafted payload.

• AuthenticationNot required

  No Woodpecker account or privileged access is needed; the attacker only needs the ability to open a merge request on the target GitLab repository, which is typically available to any authenticated GitLab user on public or open projects.

• Victim interactionNot required

  No victim action is required; the pipeline trigger fires automatically when the merge request webhook is received by Woodpecker.

• Attack complexityDetail

  Attack complexity is rated High because exploitation depends on a prerequisite condition: the attacker must know or guess a username that appears in the ApprovalAllowedUsers list in order to craft the matching commit author name.

Blast Radius

• Reads all CI secrets and environment variables exposed to the pipeline run, including registry credentials, API tokens, and signing keys.
• Executes arbitrary commands on the Woodpecker agent host within the pipeline execution context.
• Modifies build artifacts or injects malicious code into the build output before it is published or deployed.
• Causes denial of service for legitimate pipeline runs by exhausting agent capacity or corrupting shared state.