CVE-2026-58439 in Gitea
Summary
by MITRE • 08/13/2026
Branch Protection Bypass via PR Retargeting Preserves Stale `official` Approval Flag
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Analysis
by VulDB Data Team • 08/13/2026
This vulnerability involves a sophisticated branch protection mechanism bypass that exploits the retention of stale approval flags during pull request retargeting operations within version control systems. The flaw occurs when a pull request is retargeted from one branch to another while maintaining its original approval status, creating a dangerous scenario where outdated security approvals remain valid even after code changes have been made to different branches. This type of vulnerability directly relates to CWE-284 Access Control Bypass and can be categorized under ATT&CK technique T1578 for Valid Accounts and T1078 for Additional Cloud Credentials, as it leverages existing approval mechanisms to circumvent security controls.
The technical implementation of this vulnerability relies on the improper handling of approval metadata during branch retargeting operations. When a pull request is moved from one branch to another, the system fails to properly invalidate or update the approval status that was originally granted for code changes on the previous branch. This retention of stale approval flags creates a situation where security controls intended to prevent unauthorized code merges remain ineffective because the system incorrectly assumes that approvals remain valid across different code contexts. The underlying mechanism typically involves improper state management in the version control platform's backend systems, where approval flags are not properly synchronized with branch changes or when the retargeting process does not trigger necessary security validation procedures.
The operational impact of this vulnerability is significant as it allows malicious actors or unauthorized developers to bypass critical security gates that should prevent code merges. An attacker could manipulate a pull request by retargeting it from a protected branch to a less secure branch while preserving its approval status, effectively circumventing the security controls designed to protect sensitive code repositories. This creates a persistent backdoor where previously approved code changes can be merged into different branches without proper re-evaluation, potentially introducing vulnerabilities or unauthorized modifications that bypass all standard review processes. The impact extends beyond simple code integrity concerns as it undermines the entire security posture of software development environments and can lead to supply chain compromises.
Mitigation strategies should focus on implementing comprehensive approval flag invalidation during branch retargeting operations, ensuring that any change in branch context requires fresh approval validation. Organizations should establish automated systems that detect and prevent pull request retargeting operations that would preserve stale approval flags across different code contexts. The remediation approach must include proper state management protocols within version control platforms, implementing checks that invalidate existing approvals when a pull request is retargeted to a different branch. Security teams should also consider implementing additional verification steps that require re-approval for any code changes that occur across different branch contexts, utilizing continuous integration systems to enforce these controls and prevent bypass scenarios that could lead to unauthorized code deployments.