CVE-2026-28431

Misskey lacks proper authorization checks and input validation

State: Published
Severity: 9.2 Critical
Published: Mar 9, 2026
Updated: Mar 10, 2026
Reserved: Feb 27, 2026

Description

Misskey is an open source, federated social media platform. All Misskey servers running versions 8.45.0 and later, but prior to 2026.3.1, contain a vulnerability that allows bad actors access to data that they ordinarily wouldn't be able to access due to insufficient permission checks and proper input validation. This vulnerability occurs regardless of whether federation is enabled or not. This vulnerability could lead to a significant data breach. This vulnerability is fixed in 2026.3.1.

Scores

CVSS	Score	Vector	Source
4.0	9.2 Critical	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N	GitHub_M

Weaknesses

CWE-285 Improper Authorization

Affected Products

Product	Versions
misskeymisskey-dev	>= 8.45.0, < 2026.3.1Affected

References

https://github.com/misskey-dev/misskey/security/advisories/GHSA-r33c-qg3g-v9cr

Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.