VDB-346195 · CVE-2026-1046 · EUVD-2026-6090

Mattermost Desktop App up to 5.2.13/6.2.0 Help Menu improper authorization in handler for custom url scheme

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.
6.3	$0-$5k	0.00

Summaryinfo

A vulnerability has been found in Mattermost Desktop App up to 5.2.13/6.2.0 and classified as problematic. This vulnerability affects unknown code of the component Help Menu Handler. This manipulation causes improper authorization in handler for custom url scheme. This vulnerability is registered as CVE-2026-1046. Remote exploitation of the attack is possible. No exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as problematic was found in Mattermost Desktop App up to 5.2.13/6.2.0. Affected by this vulnerability is an unknown part of the component Help Menu Handler. The manipulation with an unknown input leads to a improper authorization in handler for custom url scheme vulnerability. The CWE definition for the vulnerability is CWE-939. The product uses a handler for a custom URL scheme, but it does not properly restrict which actors can invoke the handler using the scheme. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Mattermost Desktop App versions <=6.0 6.2.0 5.2.13.0 fail to validate help links which allows a malicious Mattermost server to execute arbitrary executables on a user’s system via the user clicking on certain items in the Help menu Mattermost Advisory ID: MMSA-2026-00577

The weakness was published by hackerman70000. It is possible to read the advisory at mattermost.com. This vulnerability is known as CVE-2026-1046 since 01/16/2026. The exploitation appears to be difficult. The attack can be launched remotely. The exploitation doesn't need any form of authentication. It demands that the victim is doing some kind of user interaction. The technical details are unknown and an exploit is not publicly available.

Upgrading to version 5.13.3.0, 6.0.3.0 or 6.1.0 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-6090). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

Groupware Software

Vendor

Mattermost

Name

Desktop App

Version

License

open-source

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.4
VulDB Meta Temp Score: 6.3

VulDB Base Score: 5.0
VulDB Temp Score: 4.8
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 6.5
NVD Vector: 🔒

CNA Base Score: 7.6
CNA Vector (Mattermost): 🔒

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Improper authorization in handler for custom url scheme
CWE: CWE-939 / CWE-285 / CWE-266
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

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Desktop App 5.13.3.0/6.0.3.0/6.1.0

Timelineinfo

01/16/2026 CVE reserved
02/16/2026 +31 days Advisory disclosed
02/16/2026 +0 days VulDB entry created
03/23/2026 +35 days VulDB entry last update

Sourcesinfo

Advisory: mattermost.com
Researcher: hackerman70000
Status: Confirmed

CVE: CVE-2026-1046 (🔒)
GCVE (CVE): GCVE-0-2026-1046
GCVE (VulDB): GCVE-100-346195
EUVD: 🔒

Entryinfo

Created: 02/16/2026 16:00
Updated: 03/23/2026 18:44
Changes: 02/16/2026 16:00 (65), 02/17/2026 18:10 (1), 02/20/2026 09:54 (1), 03/23/2026 18:44 (11)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.