CVE-2026-6333
Last modified
CVE-2026-6333 is a medium-severity vulnerability rated 5/10 on the CVSS scale. 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. EPSS estimates a 0.14% chance of exploitation in the next 30 days.
Description
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
Metrics
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Mattermost | Mattermost Server | >= 10.11.0, < 10.11.14 |
| Mattermost | Mattermost Server | >= 11.5.0, < 11.5.2 |
References
- https://mattermost.com/security-updatesVendor Advisory
Timeline
- Published
- Last Modified
- Status
- Analyzed
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