CVE-2026-28433 Misskey lacks resource ownership validation

What is CVE-2026-28433?

CVE-2026-28433 is a low-severity missing authorization vulnerability in misskey-dev misskey, published on 9 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

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.

Weakness: CWE-862, CWE-639

Which versions are affected by CVE-2026-28433?

It affects 1 product.

Products include Misskey Misskey.

How do I fix CVE-2026-28433?

No fix has been published for CVE-2026-28433 yet. Limit exposure of the affected software until one is available.

Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.

Is CVE-2026-28433 being exploited?

There is no known exploitation of CVE-2026-28433 in the wild and no public exploit code.

Other vulnerabilities in misskey-dev misskey

• CVE-2025-25306 Misskey's Incomplete Patch of CVE-2024-52591 Leads to Forgery of Federated Notes Critical 9.3
• CVE-2023-49079 Misskey's missing signature validation allows arbitrary users to impersonate any remote user. Critical 9.3
• CVE-2026-28431 Misskey lacks proper authorization checks and input validation Critical 9.2
• CVE-2023-52139 Misskey vulnerable to improper authorization when accessing with third-party application Critical 9.1
• CVE-2024-52590 Missing validation allows spoofed profiles in Misskey High 8.8

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-g6hj-33h7-6fq8.