CVE-2026-6339

Published: Mag 18, 2026 Last Modified: Mag 18, 2026
ExploitDB:
Other exploit source:
Google Dorks:
MEDIUM 4,3
Source: [email protected]
Attack Vector: network
Attack Complexity: low
Privileges Required: low
User Interaction: none
Scope: unchanged
Confidentiality: none
Integrity: none
Availability: low

Description

AI Translation Available

Mattermost versions 11.5.x <= 11.5.1, 11.4.x <= 11.4.3 fail to validate the X-Requested-With header on the burn-on-read reveal endpoint which allows an authenticated channel member to force the reveal of a burn-on-read message without recipient consent via a crafted Markdown image tag.. Mattermost Advisory ID: MMSA-2026-00636

EPSS (Exploit Prediction Scoring System)

Trend Analysis

EPSS (Exploit Prediction Scoring System)

Prevede la probabilità di sfruttamento basata su intelligence sulle minacce e sulle caratteristiche della vulnerabilità.

EPSS Score
0,0001
Percentile
0,0th
Updated

EPSS Score Trend (Last 2 Days)

346

Origin Validation Error

Draft
Abstraction: Class Structure: Simple
Common Consequences
Security Scopes Affected:
Access Control Other
Potential Impacts:
Gain Privileges Or Assume Identity Varies By Context
Applicable Platforms
Technologies: Not Technology-Specific, Web Based
View CWE Details
Application

Mattermost Server by Mattermost

Product Information
Vendor Mattermost
Product Mattermost Server
Version Range Affected
From 11.5.0 (inclusive)
To 11.5.2 (exclusive)
cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
Application

Mattermost Server by Mattermost

Product Information
Vendor Mattermost
Product Mattermost Server
Version Range Affected
From 11.4.0 (inclusive)
To 11.4.4 (exclusive)
cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
https://mattermost.com/security-updates
https://mattermost.com/security-updates