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

Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to properly validate team membership when searching channels which allows a removed team member to enumerate all public channels within a private team via the channel search API endpoint.. Mattermost Advisory ID: MMSA-2025-00568

Fields is a GLPI plugin that allows users to add custom fields on GLPI items forms. Prior to version 1.23.3, it is possible to execute arbitrary PHP code from users that are allowed to create dropdowns. This issue has been patched in version 1.23.3.

HCL AION is affected by a vulnerability where certain identifiers may be predictable in nature. Predictable identifiers may allow an attacker to infer or guess system-generated values, potentially leading to limited information disclosure or unintended access under specific conditions.

When an Expat parser with a registered ElementDeclHandler parses an inline document type definition containing a deeply nested content model a C stack overflow occurs.

Mattermost versions 10.11.x <= 10.11.10 fail to validate user's authentication method when processing account auth type switch which allows an authenticated attacker to change account password without confirmation via falsely claiming a different auth provider.. Mattermost Advisory ID: MMSA-2026-00583

HCL AION is affected by a vulnerability where model packaging and distribution mechanisms may not include sufficient authenticity verification. This may allow the possibility of unverified or modified model artifacts being used, potentially leading to integrity concerns or unintended behaviour.

HCL AION is affected by a vulnerability related to the handling of upload size limits. Improper control or validation of upload sizes may allow excessive resource consumption, which could potentially lead to service degradation or denial-of-service conditions under certain scenarios.

The fix for CVE-2026-0672, which rejected control characters in http.cookies.Morsel, was incomplete. The Morsel.update(), |= operator, and unpickling paths were not patched, allowing control characters to bypass input validation. Additionally, BaseCookie.js_output() lacked the output validation applied to BaseCookie.output().

Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to bound memory allocation when processing DOC files which allows an authenticated attacker to cause server memory exhaustion and denial of service via uploading a specially crafted DOC file.. Mattermost Advisory ID: MMSA-2026-00581