CVE-2026-109553

highpriority · track · 0EPSS 0.002 · 9 %ileRU
grimoire priorityP2 · Scheduled
Exploitable?
—
no known exploitation
Likely / severe?
0.20% (9th) EPSS
CVSS 7.5 · high
Is it mine?
1 products
Check your exposure
Who says so?
1 sources
fstec_bdu

EPSS · scored 2026-10-23

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.

01

cvss

Technical severity, 0–10. One row per scoring source.

7.5
010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.9–7.5

v3.17.5highAV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:Hsecondary · FSTEC (BDU) RU
v3.17.5highCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:Hsecondaryexploitability 1.6 · impact 5.9
v3.16.9mediumCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:Usecondary · CVSS-BT (t0sche)
02

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-287US
03

affected products (1)

Products and version ranges known to be affected.

04

also known as (2)

Other names and identifiers for this entity.

05

sources

Which sources assert this record, and when.

fstec_bduNVDCVE.orgMITRE
published 2026-10-18modified 2026-10-21
06

references (5) nvd

External citations — patches, advisories, analysis.

scry

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