Misskey
CVE-2026-28431
HIGH
Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Primary rating from GitHub Advisory · only source for this CVE.
CVSS VectorGitHub Advisory
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Lifecycle Timeline
2DescriptionGitHub Advisory
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.
AnalysisAI
Misskey is an open source, federated social media platform.
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Misskey versions 8.45.0 through 2026.3.0 running with default configuration. … Additional conditions and limiting factors are described in the full assessment. |
| Exploit Scenario | An attacker could exploit this vulnerability to a significant data breach. |
| Remediation | Fixed in version 2026.3.1.. Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours: Inventory all Misskey deployments and assess whether they are internet-facing or internally used; isolate critical instances if possible and review access logs for suspicious activity. …
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