CVE-2026-20896 Details.
Gitea Docker Image <= 1.26.2 - Reverse Proxy Header Authentication Bypass
Atlas does not check this one. Needs a scripted sequence.
This check is a series of requests where each step depends on the last, often after logging in. Atlas runs single, read-only probes, so it does not run this one.
About CVE-2026-20896. What It Means.
The official Gitea Docker image through version 1.26.2 ships with REVERSE_PROXY_TRUSTED_PROXIES set to a wildcard, causing Gitea to trust reverse-proxy authentication headers (X-WEBAUTH-USER) from any source IP instead of restricting trust to the configured reverse proxy. When reverse-proxy authentication is enabled, an unauthenticated remote attacker can impersonate any existing user, including an administrator, by sending the target username in the X-WEBAUTH-USER header.
Affected Product. What Is Hit.
- Vendor
- gitea
- Product
- Gitea
FAQ
Common Questions.
Gitea Docker Image <= 1.26.2 - Reverse Proxy Header Authentication Bypass. The official Gitea Docker image through version 1.26.2 ships with REVERSE_PROXY_TRUSTED_PROXIES set to a wildcard, causing Gitea to trust reverse-proxy authentication headers (X-WEBAUTH-USER) from any source IP instead of restricting trust to the configured reverse proxy. When reverse-proxy authentication is enabled, an unauthenticated remote attacker can impersonate any existing user, including an administrator, by sending the target username in the X-WEBAUTH-USER header.
No. This check is a series of requests where each step depends on the last, often after logging in. Atlas runs single, read-only probes, so it does not run this one. The facts about CVE-2026-20896 are on this page, and you can request a demo to see how Brandefense watches your whole external attack surface.
CVE-2026-20896 is not on the CISA Known Exploited Vulnerabilities list at the time of writing, but it is still worth fixing.
Update Gitea to the latest version from the vendor, or follow the vendor's advice to switch off the affected feature. Vendor links are listed on this page when they are known.
This page lists the public facts about CVE-2026-20896. Atlas does not run a check for it, so nothing here says whether a particular site is affected.