CVE-2026-20719

DoS via URL Previews Rendering Malicious SVGs

State: Published
Severity: 4.3 Medium
Published: Mar 25, 2026
Updated: Mar 26, 2026
Reserved: Feb 23, 2026

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

Scores

CVSS	Score	Vector	Source
3.1	4.3 Medium	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L	Mattermost

Weaknesses

CWE-754 Improper Check for Unusual or Exceptional Conditions

Affected Products

Product	Versions
MattermostMattermost	11.4.0 through 11.4.0Affected 11.3.0 through 11.3.1Affected 11.2.0 through 11.2.3Affected 10.11.0 through 10.11.11Affected 11.5.0Not affected 11.4.1Not affected 11.3.2Not affected 11.2.4Not affected 10.11.12Not affected

References

MMSA-2026-00595vendor-advisory

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