CVE-2025-48937Network attack vector

Encrypted-event sender spoofing via missing identity check

Published Jun 10, 2025 · Updated Jun 10, 2025

Authentication bypass in matrix-sdk-crypto 0.8.0 through 0.11.0 allows remote authenticated users to spoof encrypted-event senders. OlmMachine accepts an event when its room ID matches the Megolm session but fails to compare the envelope sender with the session owner's user ID. Administrator access to the recipient's homeserver is required, and successful manipulation makes a message appear to originate from another user.

CVSS severity4.9
Medium
EPSS probability0.37%
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 matrix-sdk-crypto 0.8.0 through 0.11.0 allows remote authenticated users to spoof encrypted-event senders. OlmMachine accepts an event when its room ID matches the Megolm session but fails to compare the envelope sender with the session owner's user ID. Administrator access to the recipient's homeserver is required, and successful manipulation makes a message appear to originate from another user.

The record

CVE
CVE-2025-48937
Published
Jun 10, 2025
Updated
Jun 10, 2025
Vendor
The Matrix.org Foundation
Product
matrix-rust-sdk
Classifications
CWE-290, T1565.001
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Jun 10, 2025CVE publishedPublication date reported by the CVE source.
  2. Jun 10, 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=>= 0.8.0, < 0.11.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

The Matrix.org Foundation · matrix-rust-sdkversion=>= 0.8.0, < 0.11.1

Published CVSS scores

4.9GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:H/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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-290Authentication Bypass by Spoofing
T1565.001Stored Data Manipulation

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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