Markdown image rendering bypass in AI bot tool result posts in Mattermost
Summary
| CVE | CVE-2026-3472 |
|---|---|
| State | PUBLISHED |
| Assigner | Mattermost |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-06-26 15:16:38 UTC |
| Updated | 2026-06-29 19:27:20 UTC |
| Description | 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 |
Risk And Classification
Primary CVSS: v3.1 3.5 LOW from [email protected]
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N
EPSS: 0.001900000 probability, percentile 0.088010000 (date 2026-06-29)
Problem Types: CWE-693 | CWE-693 CWE-693: Protection Mechanism Failure
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 3.5 | LOW | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N |
| 3.1 | CNA | CVSS | 3.5 | LOW | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
LowUser Interaction
RequiredScope
UnchangedConfidentiality
LowIntegrity
NoneAvailability
NoneCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N
NVD Known Affected Configurations (CPE 2.3)
| Type | Vendor | Product | Version | Update | Edition | Language |
|---|---|---|---|---|---|---|
| Application | Mattermost | Mattermost Server | All | All | All | All |
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Mattermost | Mattermost | affected 10.11.0 10.11.18 semver | Not specified |
| CNA | Mattermost | Mattermost | affected 11.6.0 11.6.3 semver | Not specified |
| CNA | Mattermost | Mattermost | affected 11.5.0 11.5.6 semver | Not specified |
| CNA | Mattermost | Mattermost | unaffected 11.7.0 | Not specified |
| CNA | Mattermost | Mattermost | unaffected 10.11.19 | Not specified |
| CNA | Mattermost | Mattermost | unaffected 11.6.4 | Not specified |
| CNA | Mattermost | Mattermost | unaffected 11.5.7 | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| mattermost.com/security-updates | [email protected] | mattermost.com | Vendor Advisory |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Juho Forsén (en)
Additional Advisory Data
Solutions
CNA: Update Mattermost to versions 11.7.0, 10.11.19, 11.6.4, 11.5.7 or higher.
There are currently no legacy QID mappings associated with this CVE.