Dashboard / CVE-2026-18799

CVE-2026-18799

MEDIUM
MEDIUM Priority: 0.01 BB Relevance: 59/100
Published: 2026-10-16 Modified: 2026-10-29 First seen: 2026-10-29 Status: active

Attack Surface

Network Low Complexity No Interaction

CVSS Vector Breakdown

AV: Network
AC: Low
PR: Low
UI: None
S: Unchanged
C: None
I: Low
A: None

Description

Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to restrict Slack import account binding to system administrator-initiated imports which allows an authenticated attacker with team admin privileges to force-add existing Mattermost users to their team and forge posts attributed to those users' identities via a crafted Slack export containing target users' email addresses.. Mattermost Advisory ID: MMSA-2026-00757

Weakness Classification (1)

Affected Software (2)

VendorProductVersion
mattermost mattermost_server 11.7.0 – 11.7.10
mattermost mattermost_server 11.10.0

References & Advisories (1)

Bug Bounty Relevance

59 / 100
✓ Network accessible
✓ Low complexity
✓ No user interaction

CVSS Score

4.3 / 10.0 v3.1
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

EPSS — Exploitation Probability

0.20%
Raw Score 0.001980
Percentile 9.6%
Date 2026-10-29

Intelligence Sources

nvd ref →

External Links