Matrix
CVE-2021-39164
LOW
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V14 - Data Protection Data exposure prevention
MITRE ATT&CK
2 techniques across 2 tactics: Collection, Discovery The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS score of 3.1 (LOW). Attack characteristics: network attack vector, high complexity, low privileges required, no user interaction not required. |
| Exploit ScenarioDerived | A remote attacker could access sensitive data that should not be disclosed by sending crafted requests to the affected application. |
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Alert meAnalysisAI
Matrix is an ecosystem for open federated Instant Messaging and Voice over IP. Rated low severity (CVSS 3.1), this vulnerability is remotely exploitable. This Exposure of Sensitive Information vulnerability could allow attackers to access sensitive data that should not be disclosed.
RemediationAI
A vendor patch is available. Apply the latest security update as soon as possible. Minimize information in error messages, implement proper access controls, encrypt sensitive data at rest and in transit.
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in pypi
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
This vulnerability is classified as Exposure of Sensitive Information (CWE-200), which allows attackers to access sensitive data that should not be disclosed. Matrix is an ecosystem for open federated Instant Messaging and Voice over IP. In versions 1.41.0 and prior, unauthorised users can access the membership (list of members, with their display names) of a room if they know the ID of the room. The vulnerability is limited to rooms with shared history visibility. Furthermore, the unauthorised user must be using an account on a vulnerable homeserver that is in the room. Server administrators should upgrade to 1.41.1 or later in order to receive the patch. One workaround is available. Administrators of servers that use a reverse proxy could, with potentially unacceptable loss of functionality, block the endpoints: /_matrix/client/r0/rooms/{room_id}/members with at query parameter, and /_matrix/client/unstable/rooms/{room_id}/members with at query parameter. Affected products include: Matrix Synapse, Fedoraproject Fedora.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionNVD
Matrix is an ecosystem for open federated Instant Messaging and Voice over IP. In versions 1.41.0 and prior, unauthorised users can access the membership (list of members, with their display names) of a room if they know the ID of the room. The vulnerability is limited to rooms with shared history visibility. Furthermore, the unauthorised user must be using an account on a vulnerable homeserver that is in the room. Server administrators should upgrade to 1.41.1 or later in order to receive the patch. One workaround is available. Administrators of servers that use a reverse proxy could, with potentially unacceptable loss of functionality, block the endpoints: /_matrix/client/r0/rooms/{room_id}/members with at query parameter, and /_matrix/client/unstable/rooms/{room_id}/members with at query parameter.
Threat Intelligence Overview
NVD
CVE.org
EPSS
GitHub
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.
Affected Products (CPE)NVD
Matrix libolm before 3.2.3 allows a malicious Matrix homeserver to crash a client (while it is attempting to retrieve an
An issue was discovered in core/assets/form/form_question_types/form_question_type_file_upload/form_question_type_file_u
An issue was discovered in Squiz Matrix CMS 5.5.0 prior to 5.5.0.3, 5.5.1 prior to 5.5.1.8, 5.5.2 prior to 5.5.2.4, and
Unauthenticated remote attackers can coerce Conduit-derived Matrix homeservers into cryptographically signing arbitrary
matrix-appservice-irc is a Node.js IRC bridge for Matrix. Rated critical severity (CVSS 9.8), this vulnerability is remo
The olm_session_describe function in Matrix libolm before 3.2.7 is vulnerable to a buffer overflow. Rated critical sever
Matrix Synapse before 1.5.0 mishandles signature checking on some federation APIs. Rated critical severity (CVSS 9.8), t
An issue was discovered in Matrix libolm through 3.2.16. Rated medium severity (CVSS 5.3), this vulnerability is remotel
An issue was discovered in Matrix libolm through 3.2.16. Rated medium severity (CVSS 5.3), this vulnerability is remotel
An issue was discovered in Squiz Matrix before 5.3.6.1 and 5.4.x before 5.4.1.3. Rated high severity (CVSS 8.8), this vu
matrix-hookshot is a Matrix bot for connecting to external services like GitHub, GitLab, JIRA, and more. Rated critical
matrix-appservice-irc is an open source Node.js IRC bridge for Matrix. Rated high severity (CVSS 8.8), this vulnerabilit
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