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Synapse CVE-2021-30493

MEDIUM
Incorrect Default Permissions (CWE-276)
2021-04-14 cve@mitre.org
5.5
CVSS 3.1 · NVD
View

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V13 - Configuration Default permission hardening
MITRE ATT&CK

1 technique across 1 tactic: Privilege Escalation

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Impact

CVSS score of 5.5 (MEDIUM). Attack characteristics: local attack vector, low complexity, low privileges required, no user interaction not required. Public proof-of-concept exploit code is available.

Exploit ScenarioDerived

A local attacker with access to the system could access resources due to overly permissive default settings.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 0.5% exploitation probability (EPSS)

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AnalysisAI

Multiple system services installed alongside the Razer Synapse 3 software suite perform privileged operations on entries within the ChromaBroadcast subkey. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity. Public exploit code available and no vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Set restrictive default permissions, follow principle of least privilege, review defaults during deployment.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

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 Incorrect Default Permissions (CWE-276), which allows attackers to access resources due to overly permissive default settings. Multiple system services installed alongside the Razer Synapse 3 software suite perform privileged operations on entries within the ChromaBroadcast subkey. These privileged operations consist of file name concatenation of a runtime log file that is used to store runtime log information. In other words, an attacker can create a file in an unintended directory (with some limitations). Affected products include: Razer Synapse.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 5.5 MEDIUM
AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

DescriptionNVD

Multiple system services installed alongside the Razer Synapse 3 software suite perform privileged operations on entries within the ChromaBroadcast subkey. These privileged operations consist of file name concatenation of a runtime log file that is used to store runtime log information. In other words, an attacker can create a file in an unintended directory (with some limitations).

Threat Intelligence Overview

EPSS Score
0.5%
Top 60% exploitable
Exploit
POC
Public exploit code exists
Data Quality
2 sources
Confidence: Low

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.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC Yes
EPSS 0.5%
Patch available No
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
Poc
System Exposure· derived
Small
Automatable· derived
No
Human Impact· derived
Medium

Priority Score

49
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +28
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Privilege escalation occurs when an attacker leverages flaws in access control mechanisms to gain permissions beyond what they were originally granted.

Affected Products (CPE)NVD

cpe:2.3:a:razer:synapse:3.5.1030.101917:*:*:*:*:*:*:*
CVE-2017-9769 CRITICAL POC
9.8 Aug 02

A specially crafted IOCTL can be issued to the rzpnk.sys driver in Razer Synapse 2.20.15.1104 that is forwarded to ZwOpe

CVE-2017-15708 CRITICAL
9.8 Dec 11

In Apache Synapse, by default no authentication is required for Java Remote Method Invocation (RMI). Rated critical seve

CVE-2019-18835 CRITICAL
9.8 Nov 08

Matrix Synapse before 1.5.0 mishandles signature checking on some federation APIs. Rated critical severity (CVSS 9.8), t

CVE-2021-30494 MEDIUM POC
5.5 Apr 14

Multiple system services installed alongside the Razer Synapse 3 software suite perform privileged operations on entries

CVE-2018-16515 HIGH
8.8 Sep 18

Matrix Synapse before 0.33.3.1 allows remote attackers to spoof events and possibly have unspecified other impacts by le

CVE-2025-30355 HIGH
7.1 Mar 27

Synapse is an open source Matrix homeserver implementation. Rated high severity (CVSS 7.1), this vulnerability is remote

CVE-2017-11652 HIGH
8.4 Aug 18

Razer Synapse 2.20.15.1104 and earlier uses weak permissions for the CrashReporter directory, which allows local users t

CVE-2023-32323 MEDIUM POC
4.3 May 26

Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. Rated medium severity (

CVE-2021-21332 HIGH
8.2 Mar 26

Synapse is a Matrix reference homeserver written in python (pypi package matrix-synapse). Rated high severity (CVSS 8.2)

CVE-2025-9871 HIGH
7.8 Oct 29

Local privilege escalation in Razer Synapse 3 lets an attacker who already holds a low-privileged foothold on a Windows

CVE-2025-9870 HIGH
7.8 Oct 29

Local privilege escalation in Razer Synapse 3 allows an attacker who already holds a low-privileged foothold on a Window

CVE-2025-9869 HIGH
7.8 Oct 29

Local privilege escalation in Razer Synapse 3 lets an attacker who already has low-privileged code execution on a Window

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