CVE-2026-109553Gitea SSH certificate principal impersonation of other users
Updated under an hour ago ()
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It affects Gitea. Add what you run to find out whether that includes you.
EPSS puts the chance of exploitation in the next 30 days at 0.20%, higher than 9% of scored CVEs.
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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
- 7.5 HIGH (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- 0.20% (percentile 9)
- Assigned by
- Gitea
- NVD analysis
- Awaiting Analysis
- Record last updated
- Oct 19, 2026
- First seen by InfoSec Signals
- Oct 18, 2026
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.