CVE-2026-2455 - Vulnerability Details - OpenCVE

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

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact Low

Integrity Impact None

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Exploitation none

Automatable no

Technical Impact partial

No data.

No data.

No data.

No data.

Advisories

No advisories yet.

Fixes

Solution

Update Mattermost to versions 11.4.0, 11.3.1, 11.2.3, 10.11.11 or higher.

Workaround

No workaround given by the vendor.

References

Link	Providers
https://mattermost.com/security-updates

History

Mon, 16 Mar 2026 19:15:00 +0000

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Mon, 16 Mar 2026 15:15:00 +0000

Type	Values Removed	Values Added
Description		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
Title		SSRF bypass via IPv4-mapped IPv6 literals
Weaknesses		CWE-918
References		https://mattermost.com/security-updates
Metrics		cvssV3_1 `{'score': 4.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N'}`

Projects

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MITRE

Status: PUBLISHED

Assigner: Mattermost

Published: 2026-03-16T14:53:31.280Z

Updated: 2026-03-16T18:38:07.619Z

Reserved: 2026-02-13T10:45:36.473Z

Link: CVE-2026-2455

Vulnrichment

Updated: 2026-03-16T18:38:00.408Z

NVD

Status : Received

Published: 2026-03-16T15:16:22.277

Modified: 2026-03-16T15:16:22.277

Link: CVE-2026-2455

Redhat

No data.

OpenCVE Enrichment

No data.

Weaknesses

CWE-918

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