Vulnerability advisory
GHSA-j5r2-4c8j-xc3m
Gitea: Open Redirect via redirect_to
Also known as CVE-2026-25779GO-2026-5448
Severity
- CVSS 4.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
Affected versions
| Affected | Fixed in |
|---|---|
| All versions before 1.26.0 | 1.26.0 |
Description
Details
Despite the validation within urlIsRelative in modules/httplib/url.go, an open redirect is still possible due to usage of directory traversal sequences plus a back-slash in the "redirect_to" parameter.
PoC
When a user uses this URL to login:
https://gitea.com/user/login?redirect_to=/a/../\example.com
They would be redirected to example.com upon a successful login to their gitea account.
Impact
- Phishing: Attackers can use trusted domain links to redirect victims to credential-harvesting pages
- OAuth/SSO Token Theft: In authentication flows, authorization codes or tokens may leak via redirect
- Referer Leakage: Sensitive URL parameters may be exposed to attacker domains via the Referer header
- Cache Poisoning: In deployments with shared caches, malicious redirects may be cached and served to other users