Matrix Synap Synapse JSON denial of service

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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.
5.6	$0-$5k	0.00

A vulnerability was found in Matrix Synap Synapse. It has been declared as problematic. Affected by this vulnerability is an unknown part of the component JSON Handler. The manipulation with an unknown input leads to a denial of service vulnerability. The CWE definition for the vulnerability is CWE-404. As an impact it is known to affect availability. The summary by CVE is:

Matrix Synapse before 1.20.0 erroneously permits non-standard NaN, Infinity, and -Infinity JSON values in fields of m.room.member events, allowing remote attackers to execute a denial of service attack against the federation and common Matrix clients. If such a malformed event is accepted into the room's state, the impact is long-lasting and is not fixed by an upgrade to a newer version, requiring the event to be manually redacted instead. Since events are replicated to servers of other room members, the impact is not constrained to the server of the event sender.

The weakness was released 11/24/2020. The advisory is shared at github.com. This vulnerability is known as CVE-2020-26890 since 10/08/2020. The attack can be launched remotely. A single authentication is necessary for exploitation. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1499 for this issue.

Upgrading to version 1.20.0 eliminates this vulnerability.

Productinfoedit

Vendor

Matrix

Name

Synap

CPE 2.3infoedit

🔒

CPE 2.2infoedit

🔒

CVSSv3infoedit

VulDB Meta Base Score: 5.9
VulDB Meta Temp Score: 5.6

VulDB Base Score: 4.3
VulDB Temp Score: 4.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 7.5
NVD Vector: 🔒

CVSSv2infoedit

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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

NVD Base Score: 🔒

Exploitinginfoedit

Class: Denial of service
CWE: CWE-404
ATT&CK: T1499

Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	unlock	unlock	unlock	unlock
Today	unlock	unlock	unlock	unlock

Threat Intelligenceinfoedit

Threat: 🔍
Adversaries: 🔍
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Economy: 🔍
Predictions: 🔍
Remediation: 🔍

Countermeasuresinfoedit

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Synap 1.20.0

Timelineinfoedit

10/08/2020 CVE assigned
11/24/2020 +47 days Advisory disclosed
11/24/2020 +0 days VulDB entry created
12/10/2020 +16 days VulDB last update

Sourcesinfoedit

Advisory: github.com
Status: Confirmed

CVE: CVE-2020-26890 (🔒)

Entryinfoedit