Summary
CVE-2026-25119 is a high-severity authentication bypass vulnerability (CWE-290) in Gogs, an open-source self-hosted Git service, affecting all versions prior to 0.14.3. When the reverse proxy authentication feature is enabled, Gogs accepts the X-WEBAUTH-USER header directly from any incoming client request without verifying that it originated from a trusted reverse proxy, allowing a remote, unauthenticated attacker to completely bypass authentication. The vulnerability is fixed in Gogs 0.14.3.
Technical details
- Root cause: The authentication logic in
internal/context/auth.goreads the configured reverse proxy authentication header (default:X-WEBAUTH-USER) directly from incoming HTTP requests without performing any validation that the request actually originated from a trusted proxy. There is zero verification of the request source before the header value is honoured as an authenticated identity. - Trigger conditions: Exploitation requires the
ENABLE_REVERSE_PROXY_AUTHENTICATION = truesetting to be active in the Gogs configuration, and network access to the Gogs service. - Attack vector: A remote, unauthenticated attacker sends an HTTP request to the Gogs service with a forged
X-WEBAUTH-USERheader set to any target username. No credentials, tokens, or prior access are required. - Impact: Complete authentication bypass — the attacker can impersonate any existing user (including administrators) or trigger automatic creation of new accounts, gaining full access to repositories and administrative functionality controlled by the impersonated account.
Affected software
- Gogs all versions prior to 0.14.3 (i.e., ≤ 0.14.2) when
ENABLE_REVERSE_PROXY_AUTHENTICATIONis enabled
Severity
CVSS v3.1 base score: 7.5 (High)
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Mitigation and recommended actions
- Immediate: Upgrade to Gogs 0.14.3 or later. This release restricts acceptance of the reverse proxy authentication header to requests originating from configured trusted proxy IP addresses only.
- If immediate patching is not feasible: Disable
ENABLE_REVERSE_PROXY_AUTHENTICATIONin the Gogs configuration, or enforce network-level controls that ensure only the trusted reverse proxy can reach the Gogs service port directly — preventing attackers from sending forged headers.
IONIX Status
The IONIX research team is tracking ongoing exploitation attempts and recommends immediate patching. Potentially affected assets are outlined in this post.

