CVE-2026-52726: Dulwich's submodule path traversal in porcelain.submodule_update / porcelain.clone(recurse_submodules=True) yields RCE via attacker-dropped .git/hooks payload

Synopsis

A path-traversal vulnerability in Dulwich, the pure-Python Git implementation, allows a malicious repository to write attacker-controlled files into the victim's .git/hooks/ directory during submodule cloning or update. The exploit is reachable over the network with no authentication required, triggered simply by cloning or updating a crafted repository. Successful exploitation drops executable hook scripts that run arbitrary code the next time any git or dulwich command fires the corresponding hook. No fix version has been published yet; HarborGuard tracks this advisory and will make a patched-image rebuild available as soon as upstream ships a release.

HarborGuard Coverage

Exploit Conditions

• Network reachabilityRequired

  The attacker serves a crafted repository over the network; the victim must be able to reach that repository endpoint to trigger the vulnerable clone or submodule-update path.

• AuthenticationNot required

  No credentials are needed; any unauthenticated caller of porcelain.clone or submodule_update against a public or self-hosted repository is sufficient to trigger the traversal.

• Victim interactionNot required

  No user action beyond the normal clone or submodule-update operation is required; the payload lands and becomes executable without any additional prompting.

• Attack complexityDetail

  Exploitation is reliable and condition-free once the victim clones the repository; no race conditions or special memory layout is required.

Blast Radius

• Attacker-controlled scripts are written with executable permissions into .git/hooks/, allowing arbitrary operating-system commands to execute under the identity of the user running git or dulwich operations.
• Any subsequent hook-triggering command (commit, merge, push, fetch, or a dulwich porcelain call) automatically runs the dropped payload without further attacker interaction.
• Depending on the runtime context, the attacker gains code execution inside the container or host process, enabling file system reads, writes, or lateral movement within the same environment.
• Confidentiality impact is not rated High in the CVSS vector, but integrity and availability of the affected workload are fully compromised through arbitrary code execution.