CVSS 3.1
6.5 mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:HCVE-2026-4054
Medium (6.5) in mattermost mattermost server. EPSS 0.2% chance of exploitation in the next 30 days. Fixed in github.com/mattermost/mattermost-server 0.0.0-20260414103857-b21ef302025e, 11.4.4, 11.4.4+incompatible.
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
Severity
- EPSS
- 0.2% chance of exploitation in the next 30 days; higher than 15% of CVEs (scores of 2026-10-31)
- CWE
- CWE-754
- Published
- Modified
- Record from
- the NVD, synced
Affected
- mattermost:mattermost_server
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-j76w-p754-g2w7 | Go | github.com/mattermost/mattermost-server | >=11.5.0 <11.5.2 | 11.5.2 |
| GHSA-j76w-p754-g2w7 | Go | github.com/mattermost/mattermost-server | >=0.0.0-20250731163400-5b955468ea1e <0.0.0-20260414103857-b21ef302025e | 0.0.0-20260414103857-b21ef302025e |
| GHSA-j76w-p754-g2w7 | Go | github.com/mattermost/mattermost-server | >=11.4.0 <11.4.4 | 11.4.4 |
| GO-2026-5454 | Go | github.com/mattermost/mattermost-server | >=0.0.0-20250731163400-5b955468ea1e <0.0.0-20260414103857-b21ef302025e >=11.4.0+incompatible <11.4.4+incompatible >=11.5.0+incompatible <11.5.2+incompatible | 0.0.0-20260414103857-b21ef302025e, 11.4.4+incompatible, 11.5.2+incompatible |