VDB-372687 · CVE-2026-5139 · GCVE-0-2026-5139

Mattermost up to 11.7.x Slash Command authorization

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.
5.3	$0-$5k	2.54-

Summaryinfo

A vulnerability was found in Mattermost up to 10.11.17/11.5.5/11.6.2/11.7.0/11.7.x. It has been rated as problematic. The impacted element is an unknown function of the component Slash Command Handler. Performing a manipulation results in authorization. This vulnerability is reported as CVE-2026-5139. The attack is possible to be carried out remotely. No exploit exists. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Mattermost up to 10.11.17/11.5.5/11.6.2/11.7.0/11.7.x. It has been classified as problematic. This affects an unknown function of the component Slash Command Handler. The manipulation with an unknown input leads to a authorization vulnerability. CWE is classifying the issue as CWE-862. The product does not perform an authorization check when an actor attempts to access a resource or perform an action. This is going to have an impact on integrity, and availability. The summary by CVE is:

Mattermost versions 11.7.x }} slash command.. Mattermost Advisory ID: MMSA-2026-00644

The weakness was disclosed by hunterxluxhug. It is possible to read the advisory at mattermost.com. This vulnerability is uniquely identified as CVE-2026-5139 since 03/30/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. The technical details are unknown and an exploit is not publicly available.

Upgrading to version 10.11.18, 11.5.6, 11.6.3, 11.7.1 or 11.8.0 eliminates this vulnerability.

Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

Groupware Software

Name

Mattermost

Version

License

open-source

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.4
VulDB Meta Temp Score: 5.3

VulDB Base Score: 5.4
VulDB Temp Score: 5.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 5.4
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: Authorization
CWE: CWE-862 / CWE-863 / CWE-285
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
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 Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Mattermost 10.11.18/11.5.6/11.6.3/11.7.1/11.8.0

Timelineinfo

03/30/2026 CVE reserved
06/22/2026 +84 days Advisory disclosed
06/22/2026 +0 days VulDB entry created
06/22/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: mattermost.com
Researcher: hunterxluxhug
Status: Confirmed

CVE: CVE-2026-5139 (🔒)
GCVE (CVE): GCVE-0-2026-5139
GCVE (VulDB): GCVE-100-372687

Entryinfo

Created: 06/22/2026 17:27
Changes: 06/22/2026 17:27 (64)
Complete: 🔍
Cache ID: 216::103