CVE-2026-6333
Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13 fail to validate the Host header when constructing response URLs for custom slash commands which allows an authenticated attacker to redirect slash command responses to an attacker-controlled server via a spoofed Host header.. Mattermost Advisory ID: MMSA-2026-00582
- CVSS 3.1
- 5.0
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:N - EPSS
- 0.1% chance of exploitation in the next 30 days; higher than 3% of CVEs (scores of 2026-10-25)
- CWE
- CWE-918
- Published
- Modified
- Record from
- the NVD, synced
Affected
- mattermost:mattermost_server
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-vqp5-2mrp-qqxg | Go | github.com/mattermost/mattermost/server/v8 | >=11.5.0 <11.5.2 | 11.5.2 |
| GHSA-vqp5-2mrp-qqxg | Go | github.com/mattermost/mattermost/server/v8 | >=10.11.0 <10.11.14 | 10.11.14 |
| GHSA-vqp5-2mrp-qqxg | Go | github.com/mattermost/mattermost/server/v8 | <8.0.0-20260325160634-e738016c5920 | 8.0.0-20260325160634-e738016c5920 |
| GHSA-vqp5-2mrp-qqxg | Go | github.com/mattermost/mattermost-server | <5.3.2-0.20260325160634-e738016c5920 | 5.3.2-0.20260325160634-e738016c5920 |
| GO-2026-5671 | Go | github.com/mattermost/mattermost-server | >=10.11.0+incompatible <10.11.14+incompatible >=11.5.0+incompatible <11.5.2+incompatible | 10.11.14+incompatible, 11.5.2+incompatible |
| GO-2026-5671 | Go | github.com/mattermost/mattermost-server/v5 | all versions | no fix published |
| GO-2026-5671 | Go | github.com/mattermost/mattermost-server/v6 | all versions | no fix published |
| GO-2026-5671 | Go | github.com/mattermost/mattermost/server/v8 | <8.0.0-20260325160634-e738016c5920 | 8.0.0-20260325160634-e738016c5920 |