Dashboard / CVE-2026-16453

CVE-2026-16453

HIGH
MEDIUM Priority: 0.01 BB Relevance: 64/100
Published: 2026-10-16 Modified: 2026-10-29 First seen: 2026-10-29 Status: active

Attack Surface

Network Low Complexity No Interaction Conf. Impact

CVSS Vector Breakdown

AV: Network
AC: Low
PR: Low
UI: None
S: Unchanged
C: High
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 verify the integrity of the SAML RelayState POST parameter which allows an authenticated SAML user to join any team, including invite-only teams, via forging the team_id or invite_id fields in the RelayState.. Mattermost Advisory ID: MMSA-2026-00727

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

64 / 100
✓ Network accessible
✓ Low complexity
✓ No user interaction

CVSS Score

7.1 / 10.0 v3.1
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N

EPSS — Exploitation Probability

0.19%
Raw Score 0.001860
Percentile 8.2%
Date 2026-10-29

Intelligence Sources

nvd ref →

External Links