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VulnerabilityPublished

CVE-2026-46713: misskey · Improper Verification of Cryptographic Signature

Affects misskeySource CVE Database V5

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Not known to be exploited · CVSS 9.2 Critical : upgrade to 2026.5.4 as a priority.

Data as of 1 Nov 2026, 22:58 UTC

CVSS 4.0 base score
9.2Critical
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 20% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 2026.5.4
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:H/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 3 Aug 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 1 Nov 2026.

What to do

Upgrade misskey and misskey-dev/misskey to 2026.5.4.

Affected software

ProductAffectedFixed in
misskey-devmisskeyAffected
  • >=12.37.0 <2026.5.4
Fixed in
  • 2026.5.4
GitHubmisskey-dev/misskeypkg:github/misskey-dev/misskeyOther threatsAffected
  • >=12.37.0 <2026.5.4
Fixed in
  • 2026.5.4

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade affected misskey instances to version 2026.5.4 or later, where the vulnerability has been fixed. No other official remediation or temporary fixes are documented. Patch status is confirmed by the vendor advisory stating the fix is in 2026.5.4.

Description

Misskey versions 12.37.0 up to but not including 2026.5.4 contain a vulnerability in the JSON-LD signature validation and compaction process. This flaw allows spoofed activities to be accepted as valid due to improper verification of cryptographic signatures. The issue is fixed in version 2026.5.4. The vulnerability has a high severity with a CVSS 4.0 score of 9.2, indicating critical impact if exploited.

References

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