Auth bypass in Misskey
CVE-2026-28431
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.
EPSS: 0.002 (16.1th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.
Affected products
- Misskey
- Misskey-dev Misskey — versions >= 8.45.0, < 2026.3.1
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-28431?
- CVE-2026-28431 is a high-severity vulnerability in Misskey, classified under Improper Authorization. CVSS score: 7.5/10. Published 2026-03-10.
- How severe is CVE-2026-28431?
- High severity. CVSS v3 base score is 7.5 out of 10.