CVE-2026-109553

7.5 HIGH 0.2% exploit odds Fix listed Auth & access Server

What it is

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.

At a glance

Exploitability: Can be exploited over the network with a low-privilege account. High risk of data exposure, data tampering, service disruption.
Exploit odds: 0.2% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-10-14 20:08 UTC ReservedThe CVE id was reserved by its CNA
2026-10-18 19:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-11-02 17:17 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.2% in the next 30 days (EPSS).
Severity: 7.5 HIGH (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-10-18 19:16 UTC
Last modified: 2026-11-02 17:17 UTC
Exploit probability: 0.2% · EPSS, next 30 days
Weakness: CWE-287 · Improper authentication
Record status: Awaiting Analysis

Attack profile CVSS 3.1 · 7.5

Attack vector: Network
Complexity: High
Privileges needed: Low
User interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

Raw vector

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Is it in your code?

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Read https://cve-list.com/agent/cve/CVE-2026-109553.md and follow it. Check whether this project is affected by CVE-2026-109553. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record