CVE-2023-38700Network attack vector

Cross-room message disclosure via room-agnostic event cache

Published Aug 4, 2023 · Updated Oct 3, 2024

Information disclosure in Matrix.org matrix-appservice-irc before 1.0.1 allows remote authenticated users to read parts of messages. MatrixHandler caches events by event ID without the room ID, so a crafted reply can retrieve a same-ID event cached from another bridged room. Exploitation requires knowledge of the target event ID and discloses only the cached portion of that message.

CVSS severity3.5
Low
EPSS probability0.60%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in Matrix.org matrix-appservice-irc before 1.0.1 allows remote authenticated users to read parts of messages. MatrixHandler caches events by event ID without the room ID, so a crafted reply can retrieve a same-ID event cached from another bridged room. Exploitation requires knowledge of the target event ID and discloses only the cached portion of that message.

The record

CVE
CVE-2023-38700
Published
Aug 4, 2023
Updated
Oct 3, 2024
Vendor
Matrix.org
Product
matrix-appservice-irc
Classifications
CWE-200
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 4, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 3, 2024Record 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=< 1.0.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Matrix.org · matrix-appservice-ircversion=< 1.0.1

Published CVSS scores

3.7NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
3.5GitHub, Inc.CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-200Exposure of Sensitive Information to an Unauthorized Actor

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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