CVE-2026-2578 — Sensitive Info Insertion into Sent Data in Mattermost Mattermost-server

CWE-201 — Sensitive Info Insertion into Sent Data6 documents5 sources
Severity
4.3MEDIUMNVD
EPSS
0.0%
top 90.81%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
4
Github.com Mattermost Mattermost-serverGithub.com Mattermost Mattermost Server V8Mattermost Server+1 more
Timeline
PublishedMar 16
Latest updateMar 23

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

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:NExploitability: 2.8 | Impact: 1.4

Affected Packages4 packages

▶NVDmattermost/mattermost_server11.3.0 — 11.3.1
▶Gogithub.com/mattermost_mattermost-server10.11.0-rc1+incompatible — 10.11.11+incompatible+6
▶Gogithub.com/mattermost_mattermost_server_v8< 8.0.0-20260127062706-c6b205f0d770
▶CVEListV5mattermost/mattermost11.3.0 — 11.3.0

🔴Vulnerability Details

4
OSV
Mattermost fails to preserve the redacted state of burn-on-read posts during deletion in github.com/mattermost/mattermost-server↗2026-03-23
▶
GHSA
Mattermost fails to preserve the redacted state of burn-on-read posts during deletion↗2026-03-16
▶
OSV
Mattermost fails to preserve the redacted state of burn-on-read posts during deletion↗2026-03-16
▶
CVEList
Information Disclosure via WebSocket Event When Deleting Unrevealed Burn on Read Posts↗2026-03-16
▶

🕵️Threat Intelligence

1
Wiz
CVE-2026-2578 Impact, Exploitability, and Mitigation Steps | Wiz↗
▶
CVE-2026-2578 — Sensitive Info Insertion into Sent Data | cvebase