{"cve":"CVE-2026-109553","nvd":{"published":"2026-10-18T19:16:32.997","modified":"2026-10-19T21:17:04.780","status":"Awaiting Analysis","description":"Gitea resolved the principals of an SSH certificate by searching the content of all stored public keys instead of only principal keys. When Gitea trusts a user certificate authority (`SSH_TRUSTED_USER_CA_KEYS`) and accepts arbitrary principals (`SSH_AUTHORIZED_PRINCIPALS_ALLOW=anything`), a user could register another user's public key line as their own principal, or a holder of a certificate signed by that authority could list it, and then authenticate as the owner of that key through the HTTP signature API and the built-in SSH server. Instances that do not trust a user certificate authority are not affected.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.5},"cwes":[],"references":["https://blog.gitea.com/release-of-28.2.0/","https://github.com/go-gitea/gitea/pull/39839","https://github.com/go-gitea/gitea/pull/39847","https://github.com/go-gitea/gitea/releases/tag/v28.2.0","https://github.com/go-gitea/gitea/security/advisories/GHSA-vcp6-2qc6-gvq3"],"products":[],"source":"nvd","synced_at":"2026-10-21T03:56:58.798400159+00:00"},"epss":{"cve":"CVE-2026-109553","score":0.00198,"percentile":0.09389,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}