CVE-2026-2578CWE-201

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

Medium · published March 16, 2026

CVSS v3.1
4.3
EPSS
0%
Percentile
23.0
In the wild
Unconfirmed
What it is

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

The record
Technical detail
CVSS v3.1
4.3 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
CVSS v4.0
Not supplied
EPSS
0.00313 · 23.0th percentile
Weakness
CWE-201 · Insertion of Sensitive Information Into Sent Data
Published
2026-03-16T11:58Z
EPSS history
Timeline
  • 16 MAR 11:58Z
    Information Disclosure via WebSocket Event When Deleting Unrevealed Burn on Read Posts
    cvelistv5