CVE-2026-93848

Mattermost OpenID discovery endpoint request bypasses outbound connection filtering, allowing SSRF by a System Administrator

Published Oct 26, 2026 CVSS 3.1 · 2.7 Low EPSS < 1% KEV · Not listed
Description
Mattermost versions 11.7.x <= 11.7.10 fail to apply outbound internal-connection filtering to the OpenID discovery endpoint request which allows a System Administrator to determine whether internal addresses and ports are reachable from the server via an unauthenticated login request that triggers the discovery fetch.. Mattermost Advisory ID: MMSA-2026-00774

Remediation

Vendor Solution

Update Mattermost to versions 11.11.0, 11.7.11 or higher.

Tracking

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Advisories

No advisories available
References
History
Type Values Removed Values Added
First Time appeared Mattermost mattermost Server
CPEs cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
Vendors & Products Mattermost mattermost Server
Type Values Removed Values Added
First Time appeared Mattermost
Mattermost mattermost
Vendors & Products Mattermost
Mattermost mattermost
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description Mattermost versions 11.7.x <= 11.7.10 fail to apply outbound internal-connection filtering to the OpenID discovery endpoint request which allows a System Administrator to determine whether internal addresses and ports are reachable from the server via an unauthenticated login request that triggers the discovery fetch.. Mattermost Advisory ID: MMSA-2026-00774
Title Mattermost OpenID discovery endpoint request bypasses outbound connection filtering, allowing SSRF by a System Administrator
Weaknesses CWE-918
References
Metrics cvssV3_1

{'score': 2.7, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
Mattermost
Published
Updated
Oct 26, 2026, 4:46 PM
Reserved
Sep 18, 2026, 6:39 PM
Status
Analyzed
Published
Oct 26, 2026, 3:16 PM
Modified
Nov 2, 2026, 6:38 PM