CVE-2026-3472

EUVD-2026-39775
Mattermost versions 10.11.x <= 10.11.18, 11.6.x <= 11.6.3, 11.5.x <= 11.5.6 fail to properly apply markdown image rendering restrictions to AI bot tool result posts, which allows an authenticated attacker to exfiltrate data to an attacker-controlled server via injecting markdown image syntax into tool result content rendered by a victim's client.. Mattermost Advisory ID: MMSA-2026-00619
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
MattermostCNA
3.5 LOW
NETWORK
LOW
LOW
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N
Base Score
CVSS 3.x
EPSS Score
Percentile: 9.3%
Affected Products (NVD)
VendorProductVersion
mattermostmattermost_server
10.11.0 ≤
𝑥
< 10.11.19
mattermostmattermost_server
11.5.0 ≤
𝑥
< 11.5.7
mattermostmattermost_server
11.6.0 ≤
𝑥
< 11.6.4
𝑥
= Vulnerable software versions
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
mattermostmattermost
10.11.0 ≤
𝑥
≤ 10.11.18
CNA
mattermostmattermost
11.6.0 ≤
𝑥
≤ 11.6.3
CNA
mattermostmattermost
11.5.0 ≤
𝑥
≤ 11.5.6
CNA
Common Weakness Enumeration
References
https://mattermost.com/security-updates