Description

Branch Protection Bypass via PR Retargeting Preserves Stale `official` Approval Flag

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "8.1",
  "pubDate": "2026-08-13T17:17:27.913Z",
  "pubdate": "2026-08-13T17:17:27.913Z",
  "executiveSummary": "This vulnerability involves a branch protection bypass mechanism residing in pull request retargeting logic that incorrectly preserves stale official approval flags.\nThe primary impact of this flaw is the potential unauthorized integration of untrusted code into protected branches, compromising code integrity and software supply chain security.\nThe vulnerability affects systems implementing pull request workflows with branch protection rules and official approval states.\nRisk implications include the circumvention of mandatory code review processes, allowing malicious or malformed changes to be merged without proper cryptographic or human verification.\nAttacker capabilities require the ability to create or modify pull requests and subsequently retarget them to alternate destination branches where stale approval flags improperly remain valid.\nExploitation requirements depend on specific platform workflows that fail to invalidate or recalculate approval statuses upon target branch modification events.",
  "technicalDetails": "The root cause of the vulnerability stems from inadequate state validation within the pull request management logic when a pull request is retargeted to a different base branch.\nSpecifically, the system fails to invalidate, clear, or reassess the stale official approval flag associated with the original pull request context upon the retargeting action.\nThe vulnerable component is the pull request state machine and branch protection enforcement engine responsible for validating approval requirements prior to merge operations.\nThe attack flow proceeds as follows: an attacker or compromised user creates a pull request targeting a non-protected or specific development branch and obtains a valid official approval.\nSubsequently, the attacker retargets the pull request to a highly sensitive, protected production branch.\nDue to the logic flaw, the merge validation checks observe the pre-existing official approval flag, which was preserved during the retargeting operation, rather than enforcing a re-evaluation against the new target branch's protection rules.\nConsequently, the branch protection mechanism is bypassed, permitting the merge of arbitrary code without meeting the designated security gates for the protected destination.\nAuthentication and privilege requirements typically require standard user access capable of opening and retargeting pull requests within the repository scope.\nNetwork exposure is contingent on the accessibility of the code hosting platform's API or web interface.\nPost-exploitation impact includes unauthorized code execution paths within production environments, tampering with software artifacts, and potential escalation of privileges via malicious code integration."
}