Authenticated RCE via Argument Injection in Gogs (NOT FIXED)

Overview Rapid7 Labs discovered a critical argument injection ( CWE-88 ) vulnerability in Gogs , a popular open-source self-hosted Git service. Rapid7 Labs scores this vulnerability as CVSSv4 9.4 (Critical). The vulnerability allows any authenticated user to achieve remote code execution (RCE) on the server by creating a pull request with a malicious branch name that injects the --exec flag into git rebase during the "Rebase before merging" merge operation. At the time of publication, the vendor has not released a patch. The exploit requires no admin privileges and no interaction with other users; an attacker operates entirely within their own account. Since Gogs ships with open registration enabled by default ( DISABLE_REGISTRATION = false ) and no limit on repository creation ( MAX_CREATION_LIMIT = -1 ), an unauthenticated attacker can simply create an account and repository on any default-configured instance. Any registered user who creates a repo is automatically its owner. From there, enabling rebase merging is a single toggle in settings, and the entire exploit chain can be operated without interaction from any other user. Alternatively, any user with write access to a repository where rebase is already enabled can exploit it directly. On instances where repository creation is restricted, an attacker still only needs write access to any repository that has (or can have) rebase merging enabled. The result is arbitrary command execution as the Gogs server process user, giving the attacker the ability to compromise the server, read every repository on the instance (including other users' private repos), dump credentials (password hashes, API tokens, SSH keys, 2FA secrets), pivot to other network-accessible systems, and modify any hosted repository's code. The latest release versions at the time of research, Gogs 0.14.2 and 0.15.0+dev (commit b53d3162 ), were confirmed to be affected. All prior versions supporting the "Rebase before merging" style are likely vulnerable as well. Product description Gogs is a lightweight, self-hosted Git service written in Go. With ~50,000 GitHub stars and over 5,000 forks , it's one of the more popular self-hosted alternatives to GitHub, commonly deployed by companies, universities, and open-source projects. A Shodan search for http.title:"Gogs" http.title:"Sign In" returns 1,141 internet-facing instances at the time of publication. The real install base is much larger since most deployments sit behind VPNs or internal networks. Credit This vulnerability was discovered by Jonah Burgess (CryptoCat), Senior Security Researcher at Rapid7, and is being disclosed in accordance with Rapid7's vulnerability disclosure policy . Impact Any Gogs instance with more than one user account is effectively "multi-tenant", meaning each user has their own repositories, credentials, and data on a shared server. This is the default for organizations, universities, and teams that use Gogs as a shared Git hosting platform. On any such