CVE-2026-20719
Received Received - Intake
SVG Rendering Vulnerability in Mattermost Allows Denial of Service

Publication date: 2026-03-25

Last updated on: 2026-03-26

Assigner: Mattermost, Inc.

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
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Meta Information
Published
2026-03-25
Last Modified
2026-03-26
Generated
2026-06-16
AI Q&A
2026-03-25
EPSS Evaluated
2026-06-14
NVD
CVE-2026-20719
EUVD
EUVD-2026-15485
Affected Vendors & Products
Showing 4 associated CPEs
Vendor Product Version / Range
mattermost mattermost_server From 10.11.0 (inc) to 10.11.12 (exc)
mattermost mattermost_server From 11.2.0 (inc) to 11.2.4 (exc)
mattermost mattermost_server From 11.3.0 (inc) to 11.3.2 (exc)
mattermost mattermost_server From 11.4.0 (inc) to 11.4.1 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-754 The product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product.
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Executive Summary

This vulnerability affects certain versions of Mattermost (11.4.x <= 11.4.0, 11.3.x <= 11.3.1, 11.2.x <= 11.2.3, 10.11.x <= 10.11.11) where the application fails to prevent rendering of external SVG files on link embeds.

Because of this failure, unauthenticated users can exploit this by creating an issue or pull request on GitHub that includes such SVGs, which causes the Mattermost web and desktop applications to crash.

Impact Analysis

The impact of this vulnerability is a denial of service condition where the Mattermost webapp and desktop app can be crashed by unauthenticated users.

This could disrupt communication and collaboration within an organization using the affected Mattermost versions.

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