by Kastro
Paper/Archive/CVE-2026-28431

CVE-2026-28431

misskey-dev misskey — Misskey lacks proper authorization checks and input validation

EPSS 0.3%CVSS 9.2
critical.is priorityof 100
31
CVSS 9.2 (CNA)9.2 / 10 × 3027.6Not in CISA KEV+300.0EPSS percentile 17.7.177 × 203.5No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
misskey>= 8.45.0, < 2026.3.1–CNA

Scores by source

GitHub_M (CNA)9.2CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: partial

References

refgithub.com/misskey-dev/misskey/security/advisories/GHSA-r33c-qg3g-v9cr