CVE-2026-6333 — SSRF via Host Header Spoofing in Custom Slash Commands

CVE-2026-6333

SSRF via Host Header Spoofing in Custom Slash Commands PUBLISHED

Description (CNA)

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

Affected (CNA)

Vendor / product	Versions
Mattermost / Mattermost	affected 11.5.0 through 11.5.1; affected 10.11.0 through 10.11.13; unaffected 11.6.0; unaffected 11.5.2; unaffected 10.11.14

CWE

CWE-918

References

https://mattermost.com/security-updates

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.