PT-2026-25758 · Mattermost · Mattermost

Winfunc · Published 2026-03-16 · Updated 2026-03-16 · CVE-2026-2455

Mitre

CVSS v3.1

4.3

4.3

Medium

Base vector

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

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

Fix

SSRF

Weakness Enumeration

CWE-918

Related Identifiers

CVE-2026-2455

Affected Products

Mattermost

References · 2

• https://mattermost.com/security-updates · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-2455 · Security Note