Executive brief
GitHub CLI is a command-line tool used by developers to interact with GitHub services. A security flaw in certain commands caused the tool to mistakenly send sensitive authentication tokens to external servers not controlled by GitHub. If these tokens were intercepted by the operators of those external sites, they could potentially be used to access private code repositories or organization data.
Technical details
GitHub CLI (gh) versions prior to 2.93.0 contain an incorrect authorization vulnerability (CWE-863) within its shared HTTP client. The client's authentication layer uses flawed host normalization logic that collapses all *.github.com subdomains to github.com, causing it to send github.com tokens to non-API sites like tuf-repo.github.com (a GitHub Pages site). Additionally, for non-GitHub hosts, the resolver incorrectly falls back to sending GH_ENTERPRISE_TOKEN if configured. This occurs during the execution of 'gh attestation', 'gh release verify', and 'gh release verify-asset' commands, which fetch metadata from external mirrors and Azure Blob Storage. Attackers controlling these external endpoints could capture valid user tokens to gain unauthorized access to GitHub resources.
Affected products
- GitHub GitHub CLI (gh) < 2.93.0
Timeline
- 2026-05-27: advisory: GitHub published a security advisory (GHSA-8xvp-7hj6-mcj9)
- 2026-05-29: disclosed: CVE-2026-48501 published to NVD