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CVE-2025-12421: mattermost server from 10.5.0 (inclusive), before 10.5.13 (exclusive), from 10.11.0 (inclusive), before 10.11.5…
CVE-2025-12421. CVSS 3.1 base score 9.9 (CRITICAL, Vendor/CNA). EPSS 0.00345 (percentile 0.26453), scored 17-Oct-2026.
Affected technology
mattermost server · from 10.5.0 (inclusive), before 10.5.13 (exclusive)
mattermost
mattermost server · from 10.11.0 (inclusive), before 10.11.5 (exclusive)
mattermost
mattermost server · from 10.12.0 (inclusive), before 10.12.2 (exclusive)
mattermost
mattermost server · from 11.0.0 (inclusive), before 11.0.3 (exclusive)
mattermost
Mattermost · 11.0.0 through 11.0.2, 10.12.0 through 10.12.1, 10.11.0 through 10.11.4, 10.5.0 through 10.5.12
Mattermost
Description’s affected range: versions 11.0.x <= 11.0.2
Component: Not specified by the source
Attack conditions (Vendor/CNA, CVSS 3.1): Network (remote) · Low privileges required · No user interaction required
What an attacker can do
An authenticated user can perform account takeover via a specially crafted email address used when switching authentication methods and sending a request to the /users/login/sso/code-exchange endpoint. Vendor/CNA’s CVSS 3.1 assessment (base score 9.9/10) rates confidentiality, integrity and availability impact as high.
- CWE
- CWE-303
- CCR priority
- 39.7 /100 (P4)
- CVSS 3.1
- 9.9 /10 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H · Vendor/CNA
- EPSS
- 0.00345 · percentile 0.26453 · 2026-10-17
- KEV
- no
Provenance
- NVD CVE API 2.0 · Source record · observed 2026-10-19 14:02:10.907757+00:00 UTC
Stable permalink: https://cybercodered.org/item/cve-cve-2025-12421.html