CVE-2026-4054

🔶 medium

Summary

Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 Fail to validate the response body of proxied images, which allows a remote attacker to enact client-side DoS via an SVG file served from an attacker-controlled origin under a non-SVG Content-Type header (e.g. image/png) embedded in an og:image meta tag or Markdown image link.. Mattermost Advisory ID: MMSA-2026-00630

CVSS Score

4.3

Medium

EPSS Score

0.1

Exploit Probability

Published Date

2026-05-15

First Seen: 2026-05-17

📊 Relative Risk Intelligence

This CVE is Lower Risk - more severe than 5.4% of all 342,933 vulnerabilities in our database.

#324,524

Below average severity

Severity Percentile

🎯 CISA SSVC Assessment Updated: May 15, 2026

🔍 Exploitation Status

None

No known exploits

⚙️ Automatable

Requires human interaction

💥 Technical Impact

Partial

Limited system impact

🏆 Discovered By

mk7120

SSVC data provided by CISA

Last Modified 2026-05-18

Source NVD 🔗

CVSS Vector 3.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L

CWE IDs (Weakness Types)

CWE-754

📦 Affected Products 3

Vendor	Product	Status	Affected Versions
mattermost	mattermost_server	Affected	> 10.11.0 < 10.11.14
mattermost	mattermost_server	Affected	> 11.4.0 < 11.4.4
mattermost	mattermost_server	Affected	> 11.5.0 < 11.5.2

🔗 References 1

https://mattermost.com/security-updates

Vendor Advisory

🔗 Related CVEs 6

CVE ID	Severity	CVSS	EPSS	Summary	Published
CVE-2026-7521	🔶 medium	5.5	0.3	Mattermost versions 11.8.x <= 11.8.0, 11.7.x <= 11.7.3, 11.6.x <= 11.6.5, 10.11.x <= 10.11.20 fail to verify file deleti...	2026-07-28
CVE-2026-10600	🔶 medium	4.3	0.2	Mattermost versions 11.8.x <= 11.8.0, 11.7.x <= 11.7.3, 11.6.x <= 11.6.5, 10.11.x <= 10.11.20 fail to bound the time and...	2026-07-27
CVE-2026-10819	🔶 medium	6.5	0.2	Mattermost versions 11.6.x <= 11.6.5, 10.11.x <= 10.11.20, 11.8.x <= 11.8.1, 11.7.x <= 11.7.4 fail to limit the number o...	2026-07-27
CVE-2026-10085	🔶 medium	5.4	0.2	Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to restrict the group_constrained chann...	2026-07-13
CVE-2026-10103	🔶 medium	4.3	0.2	Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to verify post ownership in the shared ...	2026-07-13
CVE-2026-10106	🔶 medium	6.5	0.2	Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to verify that the channel referenced i...	2026-07-13

These CVEs affect the same products