VDB-366801 · CVE-2026-45076 · GHSA-6qf2-7x63-mm6v

element-hq synapse up to 1.152.0 denial of service

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
2.7	$0-$5k	0.00

Summaryinfo

A vulnerability, which was classified as problematic, has been found in element-hq synapse up to 1.152.0. The affected element is an unknown function. Performing a manipulation results in denial of service. This vulnerability is identified as CVE-2026-45076. The attack can be initiated remotely. There is not any exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in element-hq synapse up to 1.152.0. It has been classified as problematic. This affects an unknown functionality. The manipulation with an unknown input leads to a denial of service vulnerability. CWE is classifying the issue as CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. This is going to have an impact on availability. The summary by CVE is:

Synapse is an open source Matrix homeserver implementation. Prior to 1.152.1, in federated rooms, malicious homeservers can craft room events in such a way that prevents Synapse from providing full history to paginating clients. Clients could therefore fail to display room history. This vulnerability is fixed in 1.152.1.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-45076 since 05/08/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. The exploitation needs additional levels of successful authentication. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1499 for this issue.

The vulnerability scanner Nessus provides a plugin with the ID 318084 (Linux Distros Unpatched Vulnerability : CVE-2026-45076), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 1.152.1 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (318084). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Vendor

element-hq

Name

synapse

Version

1.152

Website

Product: https://github.com/element-hq/synapse/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 2.7
VulDB Meta Temp Score: 2.7

VulDB Base Score: 2.7
VulDB Temp Score: 2.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 2.7
NVD Vector: 🔒

CVSSv2info

AV	AC	Au	C	I	A
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💳	💳	💳	💳	💳	💳
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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Denial of service
CWE: CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Nessus ID: 318084
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2026-45076

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: synapse 1.152.1

Timelineinfo

05/08/2026 CVE reserved
05/28/2026 +20 days Advisory disclosed
05/28/2026 +0 days VulDB entry created
06/07/2026 +10 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: GHSA-6qf2-7x63-mm6v
Status: Confirmed

CVE: CVE-2026-45076 (🔒)
GCVE (CVE): GCVE-0-2026-45076
GCVE (VulDB): GCVE-100-366801

Entryinfo

Created: 05/28/2026 20:02
Updated: 06/07/2026 03:19
Changes: 05/28/2026 20:02 (67), 06/01/2026 21:00 (2), 06/07/2026 03:19 (10)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.