SSRF via Host Header Spoofing in Custom Slash Commands
8Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 3.5epss 0.1%
exploitation probability
0.1%top 96% of all CVEs
observed exploitation
nono source reports it
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
Mattermost · MattermostReferences
https://mattermost.com/security-updates