CVE-2026-20719

DoS via URL Previews Rendering Malicious SVGs

Published Mar 25, 2026 CVSS 3.1 · 4.3 Medium EPSS < 1% KEV · Not listed
Description
Mattermost versions 11.4.x <= 11.4.0, 11.3.x <= 11.3.1, 11.2.x <= 11.2.3, 10.11.x <= 10.11.11 fail to prevent rendering of external SVGs on link embeds which allows unauthenticated users to crash the Mattermost webapp and desktop app via creating an issue or PR on GitHub.. Mattermost Advisory ID: MMSA-2026-00595

Remediation

Vendor Solution

Update Mattermost to versions 11.5.0, 11.4.1, 11.3.2, 11.2.4, 10.11.12 or higher.

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-86vc-mg26-fj6x Mattermost: Authenticated DoS through failure to prevent rendering of external SVGs on link embeds
References
History
Type Values Removed Values Added
First Time appeared Mattermost mattermost Server
CPEs cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
Vendors & Products Mattermost mattermost Server
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Mattermost
Mattermost mattermost
Vendors & Products Mattermost
Mattermost mattermost
Type Values Removed Values Added
Description Mattermost versions 11.4.x <= 11.4.0, 11.3.x <= 11.3.1, 11.2.x <= 11.2.3, 10.11.x <= 10.11.11 fail to prevent rendering of external SVGs on link embeds which allows unauthenticated users to crash the Mattermost webapp and desktop app via creating an issue or PR on GitHub.. Mattermost Advisory ID: MMSA-2026-00595
Title DoS via URL Previews Rendering Malicious SVGs
Weaknesses CWE-754
References
Metrics cvssV3_1

{'score': 4.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
Mattermost
Published
Updated
Mar 26, 2026, 5:11 PM
Reserved
Feb 23, 2026, 10:07 PM
Status
Analyzed
Published
Mar 25, 2026, 5:16 PM
Modified
Jun 17, 2026, 10:17 AM