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TI-2026-35246 Aliases CVE-2026-47746

Misskey: JSON-LD signature validation + compaction is vulnerable to timing attacks

Priority LOW 38CWE-367Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
High
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
None · High · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

Misskey is an open source, federated social media platform. Versions 12.37.0 and later, but prior to 2026.5.4, are vulnerable to timing attacks during JSON-LD signature validation and the compaction process. Because the JSON-LD parsing context is not shared between signature verification and subsequent processing, the application may trust information that should not be trusted, resulting in a time-of-check to time-of-use (TOCTOU) flaw. This allows an attacker to have fraudulent activities accepted as valid, leading to a loss of integrity. This issue has been fixed in version 2026.5.4.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00282 20th percentileScored 2026-11-07
Fix Fixed misskey (misskey-dev): 2026.5.4

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
misskey-devmisskey12.37.0 to before 2026.5.42026.5.4Patch availableCNA
  • misskey Vendormisskey-dev Affected 12.37.0 to before 2026.5.4 Fixed in 2026.5.4 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:misskey:misskey:*:*:*:*:*:*:*:*——misskey-dev
  • cpe:2.3:a:misskey:misskey:*:*:*:*:*:*:*:* Versions — — ·misskey-dev

Remediation

  • Fix · CNA misskey (misskey-dev) Fixed in 2026.5.4

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-47746

References

Other 2

  • TI-2025-18599 Misskey CSRF vulnerability due to insecure configuration of authentication cookie attributes CVSS 3.1HIGH 8.2
  • TI-2025-29081 Misskey CSS Style Injection Vulnerability In `MkUrlPreview` CVSS 3.1HIGH 7.2
  • TI-2025-40906 Misskey has a login rate limit bypass via spoofed X-Forwarded-For header CVSS 4.0MEDIUM 6.9
  • TI-2025-29276 Misskey Directory Traversal Vulnerability in AiScript via `Mk:api` CVSS 3.1HIGH 7.5
  • TI-2025-40839 misskey.js's export data contains private post data CVSS 4.0HIGH 7.1
  • TI-2025-29271 @misskey-dev/summaly Redirect Filter Bypass CVSS 4.0LOW 2.1
See all 38 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences