CVE-2026-6333CWE-918ssrf

CVE-2026-6333

Low · published May 18, 2026

CVSS v3.1
3.5
EPSS
0%
Percentile
2.8
In the wild
Unconfirmed
What it is

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

The record
Technical detail
CVSS v3.1
3.5 · LOW
Vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:L/A:N
CVSS v4.0
Not supplied
EPSS
0.00137 · 2.8th percentile
Weakness
CWE-918 · Server-Side Request Forgery (SSRF)
Published
2026-05-18T13:16Z
Affected products (2)
ProductVersionsFixed in
mattermost/mattermost_server≥ 10.11.0, < 10.11.1410.11.14
mattermost/mattermost_server≥ 11.5.0, < 11.5.211.5.2
References (1)
https://mattermost.com/security-updates · [email protected]
EPSS history
Timeline
  • 18 MAY 08:41Z
    SSRF via Host Header Spoofing in Custom Slash Commands
    cvelistv5