CVE-2026-2455 MEDIUM

CVE-2026-2455: SSRF bypass via IPv4-mapped IPv6 literals

Vendor Mattermost
Product Mattermost
Weakness CWE-918 · SSRF
Published March 16, 2026
Last update March 16, 2026
View on NVD All CVEs

CVSS base score

4.3/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality Low
Integrity None

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

What the vulnerability does

01Description

Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to canonicalize IPv4-mapped IPv6 addresses before reserved IP validation which allows an attacker to perform SSRF attacks against internal services via IPv4-mapped IPv6 literals (e.g., [::ffff:127.0.0.1]).. Mattermost Advisory ID: MMSA-2026-00585

Key dates

02Disclosure timeline

March 16, 2026 CVE published
March 16, 2026 Record updated