Gitea security advisory (AV26-845)

Gitea before 1.27.1 contains a critical code injection flaw (CWE-94) in the diffpatch API that allows remote code execution by causing the installation of a Git hook. An attacker can submit a crafted request through the diffpatch API to plant a Git hook, which then executes arbitrary shell commands on the server when Git operations run; the CVSS vector indicates the attack requires no authentication or user interaction, while public reporting describes attackers with repository write access planting hooks to run shell commands. Successful exploitation yields full server compromise (confidentiality, integrity, and availability all rated high), and observed attacks have reportedly dropped a cryptocurrency miner. All Gitea deployments running versions prior to 1.27.1 are affected, with internet-facing instances at greatest risk; public scans identified over 8,300 vulnerable Gitea servers. The flaw is actively exploited in the wild: CISA added it to the Known Exploited Vulnerabilities catalog on 2026-08-25, and EPSS estimates an 86.8% probability of exploitation within 30 days.

Do: Upgrade Gitea to version 1.27.1 or later immediately; organizations subject to BOD 26-04 must apply the vendor mitigation or discontinue use of unpatched cloud-hosted instances. Until patched, limit internet exposure of Gitea servers and inspect repository hook directories for unauthorized or recently modified hooks that could serve as persistence. Check for signs of compromise, including unexpected processes or cryptocurrency-miner activity, since in-the-wold attacks reportedly deploy a miner.