CVE-2023-49079Network attack vector

Remote user impersonation via incomplete inbox validation

Published Nov 29, 2023 · Updated Aug 2, 2024

Improper signature verification in Misskey before 2023.11.1-beta.1 allows remote attackers to impersonate arbitrary remote users. The ActivityPub inbox eligibility path verifies only the HTTP message signature and fails to validate the Digest and Host headers. No account is required; a forged server-to-server federation request can attribute attacker-controlled activity to another remote identity.

CVSS severity7.1
High
EPSS probability0.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper signature verification in Misskey before 2023.11.1-beta.1 allows remote attackers to impersonate arbitrary remote users. The ActivityPub inbox eligibility path verifies only the HTTP message signature and fails to validate the Digest and Host headers. No account is required; a forged server-to-server federation request can attribute attacker-controlled activity to another remote identity.

The record

CVE
CVE-2023-49079
Published
Nov 29, 2023
Updated
Aug 2, 2024
Vendor
Misskey Project
Product
Misskey
Classifications
CWE-347, T1656
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 29, 2023CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 2024Record 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=< 2023.11.1-beta.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Misskey Project · Misskeyversion=< 2023.11.1-beta.1

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
9.3GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:N
7.1Misskey ProjectCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:H/VA:N/SC:N/SI:N/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 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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