CVE-2022-39264Network attack vector

Cross-signing key replacement via unverified secret replies

Published Sep 28, 2022 · Updated Apr 23, 2025

Improper authentication in Nheko before 0.10.2 allows remote attackers controlling the homeserver to replace stored cross-signing keys. The secret-reply handler stores a returned secret without requiring a verified sending device and key or confirming that the reply matches an active request. Exploitation requires the first reply after device verification or a manual secret request, enabling future trust in attacker-supplied cross-signing keys or an online key backup.

CVSS severity8.6
High
EPSS probability0.69%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authentication in Nheko before 0.10.2 allows remote attackers controlling the homeserver to replace stored cross-signing keys. The secret-reply handler stores a returned secret without requiring a verified sending device and key or confirming that the reply matches an active request. Exploitation requires the first reply after device verification or a manual secret request, enabling future trust in attacker-supplied cross-signing keys or an online key backup.

The record

CVE
CVE-2022-39264
Published
Sep 28, 2022
Updated
Apr 23, 2025
Vendor
Nheko-Reborn
Product
Nheko
Classifications
CWE-287, CWE-295, T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 28, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 23, 2025Record 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=< 0.10.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Nheko-Reborn · Nhekoversion=< 0.10.2

Published CVSS scores

5.9NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
8.6GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A: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-287Improper Authentication
CWE-295Improper Certificate Validation
T1557Adversary-in-the-Middle

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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