EUVD-2026-30755Published

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-c…

Exact source revision recorded 7 Nov 2026 13:29:23 UTC. It does not establish the source's current position. Latest evidence.

Recorded JSON

euvd · EUVD-2026-30755

Published

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

EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.

Original publisher date fields

datePublished: May 18, 2026, 8:41:29 AM

dateUpdated: May 19, 2026, 5:19:42 PM

Source published: May 18, 2026, 8:41:29 AM (timezone not stated)
Source modified: May 19, 2026, 5:19:42 PM (timezone not stated)
Observed here: 7 Nov 2026 13:29:23 UTC
Source terms: ENISA EUVD · source terms and attribution apply

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 3.1 · 3.5 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:L/A:N