CVE-2026-109553
Tenable Plugin
Checking the public Tenable catalog…
Threat Intelligence Pending
IOCs, MITRE ATT&CK techniques, and attack chain data are being generated. Refresh in a few seconds.
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.
Quick Facts
| CVE ID | CVE-2026-109553 |
| CVSS Score | 7.5 |
| Vector | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H |
| Published | 2026-10-18 |
| Exploited | No |
| CISA KEV | No |
| PoC | Not public |