CVE-2026-6333
SSRF via Host Header Spoofing in Custom Slash Commands
Vexday Risk Score
8Low
SSVC decision (CISA)
Track
No exploitation signal → monitor
CVSS 3.5EPSS 0.1%KEV nãoPoC —Nuclei —Metasploit —Patch referenciado
Lifecycle
18 May 2026Published on NVD
Recommendation: Monitor — no exploitation signal at the moment.
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/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:L/A:N
Affected products
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https://mattermost.com/security-updates