CVE-2026-28431CWE-285

Misskey lacks proper authorization checks and input validation

Critical · published March 9, 2026

CVSS v4.0
9.2
EPSS
0%
Percentile
34.0
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
9.2 · CRITICAL
Vector
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
EPSS
0.00409 · 34.0th percentile
Weakness
CWE-285 · Improper Authorization
Published
2026-03-09T21:17Z
EPSS history
Timeline
  • 09 MAR 21:17Z
    Misskey lacks proper authorization checks and input validation
    cvelistv5