CVE-2026-46713Network attack vectorHinoki check available

Activity spoofing via JSON-LD named-graph restructuring

Published Aug 3, 2026 · Updated Aug 3, 2026

Improper signature verification in Misskey 12.37.0 through 2026.5.3 allows remote attackers to submit spoofed federated activities. Signature validation accepts a signed JSON-LD graph that named-graph restructuring causes compaction to interpret as a different activity. No account or user interaction is required, and the accepted activity can be attributed to a remote actor who did not issue it.

CVSS severity9.2
Critical
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Improper signature verification in Misskey 12.37.0 through 2026.5.3 allows remote attackers to submit spoofed federated activities. Signature validation accepts a signed JSON-LD graph that named-graph restructuring causes compaction to interpret as a different activity. No account or user interaction is required, and the accepted activity can be attributed to a remote actor who did not issue it.

The record

CVE
CVE-2026-46713
Published
Aug 3, 2026
Updated
Aug 3, 2026
Vendor
Misskey Project
Product
Misskey
Classifications
CWE-347, T1656
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 3, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 12.37.0, < 2026.5.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Misskey Project · Misskeyversion=>= 12.37.0, < 2026.5.4

Published CVSS scores

6.9GitHub Security AdvisoryCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:L/SA:N
9.2GitHub CNACVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:H/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-347Improper Verification of Cryptographic Signature
T1656Impersonation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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