Synapse
CVE-2023-42453
MEDIUM
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V8 - Authorization Authorization verification
MITRE ATT&CK
1 technique across 1 tactic: Defense Evasion The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS score of 4.3 (MEDIUM). Attack characteristics: network attack vector, low complexity, low privileges required, no user interaction not required. |
| Exploit ScenarioDerived | This vulnerability can be exploited remotely over the network. Successful exploitation could compromise the medium-severity affected system. |
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Alert meAnalysisAI
Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity.
RemediationAI
A vendor patch is available. Apply the latest security update as soon as possible. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.
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 under CWE-285. Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. Users were able to forge read receipts for any event (if they knew the room ID and event ID). Note that the users were not able to view the events, but simply mark it as read. This could be confusing as clients will show the event as read by the user, even if they are not in the room. This issue has been patched in version 1.93.0. Users are advised to upgrade. There are no known workarounds for this issue. Affected products include: Matrix Synapse, Fedoraproject Fedora. Version information: version 1.93.0..
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionNVD
Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. Users were able to forge read receipts for any event (if they knew the room ID and event ID). Note that the users were not able to view the events, but simply mark it as read. This could be confusing as clients will show the event as read by the user, even if they are not in the room. This issue has been patched in version 1.93.0. Users are advised to upgrade. There are no known workarounds for this issue.
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
Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.
Affected Products (CPE)NVD
A specially crafted IOCTL can be issued to the rzpnk.sys driver in Razer Synapse 2.20.15.1104 that is forwarded to ZwOpe
In Apache Synapse, by default no authentication is required for Java Remote Method Invocation (RMI). Rated critical seve
Matrix Synapse before 1.5.0 mishandles signature checking on some federation APIs. Rated critical severity (CVSS 9.8), t
Multiple system services installed alongside the Razer Synapse 3 software suite perform privileged operations on entries
Multiple system services installed alongside the Razer Synapse 3 software suite perform privileged operations on entries
Matrix Synapse before 0.33.3.1 allows remote attackers to spoof events and possibly have unspecified other impacts by le
Synapse is an open source Matrix homeserver implementation. Rated high severity (CVSS 7.1), this vulnerability is remote
Razer Synapse 2.20.15.1104 and earlier uses weak permissions for the CrashReporter directory, which allows local users t
Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. Rated medium severity (
Synapse is a Matrix reference homeserver written in python (pypi package matrix-synapse). Rated high severity (CVSS 8.2)
Local privilege escalation in Razer Synapse 3 lets an attacker who already holds a low-privileged foothold on a Windows
Local privilege escalation in Razer Synapse 3 allows an attacker who already holds a low-privileged foothold on a Window
Exploit-DB