CVE-2025-54315Network attack vector

Room-state confusion via unbound create events

Published Oct 2, 2025 · Updated Oct 2, 2025

Protocol soundness flaw in Matrix Specification before 1.16 allows remote authenticated users to make one room ID identify conflicting rooms. Before room version 12, a creating homeserver chooses a random, namespaced room ID that is not cryptographically bound to the room's create event, so a malicious federating server can present a false create event. The scenario requires federation with an untrusted homeserver; Matrix could not reproduce it in implementations because rejected-event handling blocked the conflict.

CVSS severity7.1
High
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Protocol soundness flaw in Matrix Specification before 1.16 allows remote authenticated users to make one room ID identify conflicting rooms. Before room version 12, a creating homeserver chooses a random, namespaced room ID that is not cryptographically bound to the room's create event, so a malicious federating server can present a false create event. The scenario requires federation with an untrusted homeserver; Matrix could not reproduce it in implementations because rejected-event handling blocked the conflict.

The record

CVE
CVE-2025-54315
Published
Oct 2, 2025
Updated
Oct 2, 2025
Vendor
The Matrix.org Foundation
Product
Matrix Specification
Classifications
CWE-837
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 2, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 2, 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 <1.16

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

The Matrix.org Foundation · Matrix Specificationversion=0 <1.16

Published CVSS scores

7.1MITRECVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:H/A:L

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-837Improper Enforcement of a Single, Unique Action

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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