CVE-2026-2578

MEDIUM

Information Disclosure via WebSocket Event When Deleting Unrevealed Burn on Read Posts

Title source: cna

Description

Mattermost versions 11.3.x <= 11.3.0 fail to preserve the redacted state of burn-on-read posts during deletion which allows channel members to access unrevealed burn-on-read message contents via the WebSocket post deletion event.. Mattermost Advisory ID: MMSA-2026-00579

References (1)

[Vendor Advisory] https://mattermost.com/security-updates

Scores

CVSS v3 4.3

EPSS 0.0004

EPSS Percentile 10.9%

Attack Vector NETWORK

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

CISA SSVC

Vulnrichment

Exploitation none

Automatable no

Technical Impact partial

Details

CWE

CWE-201

Status published

Products (6)

mattermost/mattermost 0 - 8.0.0-20260127062706-c6b205f0d770Go

Mattermost/Mattermost 11.3.0

Mattermost/Mattermost 11.3.1

Mattermost/Mattermost 11.4.0

mattermost/mattermost-server 0 - 5.3.2-0.20260127062706-c6b205f0d770Go

mattermost/mattermost_server 11.3.0 - 11.3.1

Published Mar 16, 2026

Tracked Since Mar 16, 2026