CORS for GitLab
medium4 checks
CORS decides which origins may read your API responses. A wildcard turns an authenticated API into a public one.
What GitLab must have
- Access-Control-Allow-Origin limited to known origins
- No wildcard combined with credentials
- No reflection of arbitrary Origin headers
- Preflight responses only allow the methods actually used
How to fix it
- 1Replace wildcards with an explicit allowlist
- 2Validate Origin before echoing it and reject unknown origins early
GitLab context
Self-hosted DevOps platform with git, CI and registries.
Password-reset account takeover (CVE-2023-7028) hit many self-hosted instances — keep it patched and behind SSO.