CVE-2026-4339 SSRF via unvalidated attachment URLs in Mattermost Agents plugin MCP server

Mattermost versions 10.11.x = 10.11.18, 11.6.x = 11.6.3, 11.5.x = 11.5.6 fail to validate attachment URLs against internal or private IP ranges in the Mattermost Agents plugin MCP server which allows an attacker with access to the MCP server in stdio mode to perform server-side request forgery SS...

CVE-2016-1781

WebKit in Apple iOS before 9.3 and Safari before 9.1 mishandles attachment URLs, which makes it easier for remote web servers to track users via unspecified vectors...