CVE-2026-20896

Over 8,300 Gitea Servers Remain Exposed to Remote Code Execution via CVE-2026-60004

Thousands of publicly accessible Gitea instances were still unpatched against CVE-2026-60004 as of late August 2026, leaving them open to remote command execution. The critical vulnerability combines abuse of the diffpatch endpoint with the ability to install and trigger attacker-controlled Git hooks, allowing unauthenticated attackers to run commands on the server. Exploitation requires only write access to a repository, which is often trivial due to default open user registration in many deployments. The issue was fixed in Gitea 1.27.1 released on July 27, 2026, and CISA added the flaw to its Known Exploited Vulnerabilities catalog with a remediation deadline of August 28 for U.S. federal agencies. In observed incidents, attackers used the access to deploy cryptocurrency miners inside Docker containers. A related authentication bypass affecting the official Docker image, CVE-2026-20896, was also noted when reverse-proxy headers such as X-WEBAUTH-USER are enabled.

Gitea Authentication Bypass Exposes Private Repositories Through Default Docker Reverse Proxy Setting

A critical authentication bypass vulnerability in Gitea, tracked as CVE-2026-20896 with a CVSS score of 9.8, allows attackers to gain administrative access and read private repositories by sending a single HTTP header. The root cause lies in the official Docker image defaulting the REVERSE_PROXY_TRUSTED_PROXIES setting to a wildcard, trusting the X-WEBAUTH-USER header from any source when reverse-proxy authentication is enabled. The researcher reproduced the full attack on a live vulnerable instance, demonstrating how an unauthenticated request could retrieve secret files such as .env containing database passwords and cloud keys. Multiple related access-control flaws were also disclosed in the same year, including CVE-2026-27771 affecting the container registry, CVE-2026-22874 in webhooks, and CVE-2026-28740 in LFS handling. The recommended fix involves explicitly setting trusted proxy IPs or disabling reverse-proxy authentication entirely and upgrading to version 1.26.4 or later. The issue highlights recurring problems with overly permissive defaults in self-hosted DevOps tools.