High · CVSS 8.7CVE-2026-103937

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

Answer in brief

CVE-2026-103937 records a High severity (CVSS 8.7) vulnerability in Misskey: Denial of service resulting from insufficient cleanup processing during file uploads. The current sources do not mark it as known exploited. The current feed maps misskey-dev/misskey (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Oct 13, 2026Updated Oct 13, 2026Source checked Oct 13, 2026First seen by HOL Oct 13, 2026Material review Oct 13, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 8.7
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 8.7. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps misskey-dev/misskey (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
misskey-dev/misskeygeneric	>=12.0.0 <=13.14.2 \|\| >=2023.9.0-beta.1 <2025.4.1 \|\| >=2025.5.0 <2026.7.0	2025.4.1, 2026.7.0

Recommended response

Check inventory. Check lockfiles and deployed manifests for misskey-dev/misskey.
Review the reported fix. Update misskey-dev/misskey to 2025.4.1 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Oct 13, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Oct 13, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Oct 13, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.