CVE-2026-27779 affects Gitea Open Source Git Server versions before 1.25.5. The vulnerability arises because the software accepts malformed or injected forwarded-proto header values during the detection of public URLs. This acceptance can lead to spoofed canonical URL generation, which is a form of improper access control (CWE-284). The CVSS 3.1 base score is 7.5, indicating a high severity with network attack vector, low attack complexity, no privileges required, no user interaction, and no confidentiality or integrity impact but high availability impact. There is no vendor advisory or patch link provided, and no known exploits have been reported. The affected versions are all versions less than 1.25.5.

The vulnerability allows attackers to spoof canonical URLs by injecting or manipulating forwarded-proto header values. While it does not impact confidentiality or integrity directly, it can cause denial of service or availability issues (as indicated by the CVSS vector). This may affect URL-based logic or security controls relying on canonical URLs within Gitea instances running affected versions.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since no official patch or remediation level is provided, users should monitor Gitea's official channels for updates. Until a fix is available, cautious handling of forwarded-proto headers and restricting access to trusted networks may reduce risk.