CVE-2026-103937: Misskey: Denial of service resulting from insufficient cleanup processing during file uploads

Severity: high (CVSS 8.7 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-13 · updated 2026-10-16
Weakness: CWE-459

Description

Misskey is an open source, federated social media platform. From 13.0.0 until 2025.4.1 and from 2025.5.0 until 2026.7.0, cleanup processing may not execute during file uploads. Repeated uploads can exhaust storage or file descriptors and deny service regardless of whether federation is enabled. This issue is fixed in version 2026.7.0.

Affected products

misskey-dev misskey: from 12.0.0, <= 13.14.2; from 2023.9.0-beta.1, < 2025.4.1; from 2025.5.0, < 2026.7.0

References

https://github.com/misskey-dev/misskey/commit/3f28489fb856e6e07a16290f3ea1e1261572b527
https://github.com/misskey-dev/misskey/pull/17750
https://github.com/misskey-dev/misskey/releases/tag/2026.7.0
https://github.com/misskey-dev/misskey/security/advisories/GHSA-m9xp-2fvm-pfmq

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