CVE-2022-39250Network attack vector

User impersonation via key/device confusion

Published Sep 29, 2022 · Updated Apr 23, 2025

Authentication bypass in The Matrix.org Foundation matrix-js-sdk before 19.7.0 allows remote attackers to impersonate users via SAS verification. During verification, the SDK checks a user identity and device separately, then signs a key selected by identifier without confirming it is the key that was verified, allowing a malicious homeserver to substitute its own cross-signing identity. Exploitation requires cooperation from a malicious homeserver and can cause devices to trust the attacker-controlled identity instead of the intended user.

CVSS severity7.5
High
EPSS probability1.00%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in The Matrix.org Foundation matrix-js-sdk before 19.7.0 allows remote attackers to impersonate users via SAS verification. During verification, the SDK checks a user identity and device separately, then signs a key selected by identifier without confirming it is the key that was verified, allowing a malicious homeserver to substitute its own cross-signing identity. Exploitation requires cooperation from a malicious homeserver and can cause devices to trust the attacker-controlled identity instead of the intended user.

The record

CVE
CVE-2022-39250
Published
Sep 29, 2022
Updated
Apr 23, 2025
Vendor
The Matrix.org Foundation
Product
matrix-js-sdk
Classifications
CWE-287, T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 29, 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=< 19.7.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Matrix.org Foundation · matrix-js-sdkversion=< 19.7.0

Published CVSS scores

7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/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 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-287Improper Authentication
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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