CVE-2022-39257Network attack vector

Message impersonation via unsolicited forwarded Megolm keys

Published Sep 28, 2022 · Updated Apr 23, 2025

Improper authentication in Matrix.org iOS SDK before 0.23.19 allows remote attackers to forge another user's encrypted messages. Its Megolm key-forwarding path accepts unsolicited forwarded room keys from other users and uses them to decrypt messages without establishing a trusted source. Exploitation requires an attacker cooperating with a malicious homeserver; resulting messages can impersonate a sender, although some clients display an authenticity warning.

CVSS severity7.5
High
EPSS probability0.81%
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 Matrix.org iOS SDK before 0.23.19 allows remote attackers to forge another user's encrypted messages. Its Megolm key-forwarding path accepts unsolicited forwarded room keys from other users and uses them to decrypt messages without establishing a trusted source. Exploitation requires an attacker cooperating with a malicious homeserver; resulting messages can impersonate a sender, although some clients display an authenticity warning.

The record

CVE
CVE-2022-39257
Published
Sep 28, 2022
Updated
Apr 23, 2025
Vendor
Matrix.org
Product
Matrix.org iOS SDK
Classifications
CWE-287, CWE-322
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=< 0.23.19

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Matrix.org · Matrix.org iOS SDKversion=< 0.23.19

Published CVSS scores

7.5GitHub, Inc.CVSS: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.

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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-322Key Exchange without Entity Authentication

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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