CVE-2026-24690: Gitea Privilege Escalation Vulnerability

CVE-2026-24690 Overview

CVE-2026-24690 is an access control weakness [CWE-284] affecting Gitea versions prior to 1.25.5. The vulnerability stems from insufficient permission checks when updating or rebasing pull request branches. Attackers can exploit this flaw over the network without authentication or user interaction. Successful exploitation impacts repository integrity by allowing unauthorized modifications to pull request branches. The Gitea project addressed the issue in the 1.25.5 release through pull requests #36465 and #36838.

Critical Impact
Unauthorized actors can update or rebase pull request branches in affected Gitea instances, undermining code review integrity and enabling potential supply chain tampering.

Affected Products

Gitea versions before 1.25.5
Self-hosted Gitea Git service instances
Downstream distributions bundling vulnerable Gitea builds

Discovery Timeline

2026-07-03 - CVE-2026-24690 published to NVD
2026-07-07 - Last updated in NVD database

Technical Details for CVE-2026-24690

Vulnerability Analysis

CVE-2026-24690 is a broken access control vulnerability in Gitea's pull request workflow. The affected code paths handle branch update and rebase operations initiated against open pull requests. Gitea failed to correctly verify that the caller held write permissions on the target repository or head branch before performing the operation.

This omission enables a remote actor to trigger branch mutations that should be restricted to authorized maintainers. Because pull request branches often serve as gating points for code review and continuous integration, unauthorized updates can bypass expected governance controls. The flaw is remotely exploitable, requires no privileges, and needs no user interaction, which broadens the exposure of internet-reachable Gitea instances.

Root Cause

The root cause is a missing authorization check in the pull request update and rebase handlers. Gitea's server-side logic accepted the operation based on request validity alone, without confirming that the requesting identity satisfied the repository's permission model. The upstream fixes in Gitea Pull Request #36465 and Gitea Pull Request #36838 introduce the missing permission verification.

Attack Vector

An attacker sends crafted HTTP requests to the Gitea API or web endpoints responsible for updating or rebasing a pull request branch. Without proper authorization checks, the server executes the branch modification. This can be leveraged to introduce or override commits under review, disrupt merge workflows, or manipulate history in ways that reviewers may not detect before merge.

No verified public exploit code is available at this time. See the Gitea Release Announcement 1.25.5 for the vendor-provided technical context.

Detection Methods for CVE-2026-24690

Indicators of Compromise

Unexpected update or rebase events on pull request branches performed by accounts without write access to the target repository
Force-push or history-rewrite entries in Gitea audit logs that do not correlate with authorized maintainer activity
Pull request head commits changing between reviewer approval and merge without a corresponding review event

Detection Strategies

Query the Gitea database and access logs for POST requests to pull request update and rebase endpoints originating from users lacking repository write permissions
Correlate Git reflog entries on server-side repositories with Gitea action logs to identify unattributed branch updates
Alert on pull request branch head-SHA changes that occur outside of expected CI or maintainer workflows

Monitoring Recommendations

Forward Gitea application logs and web server access logs to a centralized SIEM for continuous review
Enable and retain Git server-side hooks that record pre-receive and post-receive activity for pull request refs
Baseline normal contributor behavior per repository and flag deviations in branch update frequency or source IP

How to Mitigate CVE-2026-24690

Immediate Actions Required

Upgrade all Gitea instances to version 1.25.5 or later without delay
Audit recent pull request branch update and rebase events for unauthorized activity
Restrict network exposure of Gitea administrative and API endpoints to trusted networks where feasible

Patch Information

The vulnerability is resolved in Gitea Release v1.25.5. The corrective changes are tracked in Gitea Pull Request #36465 and Gitea Pull Request #36838. Administrators should review the Gitea Release Announcement 1.25.5 for upgrade guidance and any accompanying configuration notes.

Workarounds

Disable anonymous and low-privilege access to pull request update and rebase endpoints where policy permits
Enforce branch protection rules requiring signed commits and approved reviews before merge
Place Gitea behind an authenticated reverse proxy that restricts write endpoints to known contributor identities

bash

# Example: verify installed Gitea version and plan upgrade to 1.25.5
gitea --version
# Upgrade via package manager or replace the binary with the 1.25.5 release, then restart
systemctl restart gitea