Auth bypass in Misskey
CVE-2026-28433
Misskey is an open source, federated social media platform. All Misskey servers running versions 10.93.0 and later, but prior to 2026.3.1, contain a vulnerability that allows importing other users' data due to lack of ownership validation. The impact of this vulnerability is estimated to be relatively low, as bad actors would require the ID corresponding to the target file for import. This vulnerability is fixed in 2026.3.1.
Vulnerability class: IDOR (Insecure Direct Object Reference)
EPSS: 0.002 (12.8th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.
Affected products
- Misskey
- Misskey-dev Misskey — versions >= 10.93.0, < 2026.3.1
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Mitigation, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-28433?
- CVE-2026-28433 is a medium-severity vulnerability in Misskey, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 4.3/10. Published 2026-03-10.
- How severe is CVE-2026-28433?
- Medium severity. CVSS v3 base score is 4.3 out of 10.