CVE-2026-72721

The record

Discourse is an open-source discussion platform. Prior to 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, Onebox::DomainChecker.is_blocked? compares hostnames and SiteSetting.blocked_onebox_domains entries case-sensitively, allowing an attacker to bypass configured Onebox domain restrictions by changing character casing in a redirect target hostname. This issue is fixed in versions 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0.

Affected packages

Related vulnerabilities

• CVE-2026-86472 fast-uri is a dependency-free RFC 3986 URI parser for Node.js, used by Fastify and ajv. CWE-178
• CVE-2026-87876 Two case-insensitive comparisons on request-derived usernames outside the main… CWE-178
• CVE-2026-84428 fastify versions before 5.12.2 implement the case-insensitive nature of HTTP header names… CWE-178
• CVE-2026-84303 gRPC-Go is the Go language implementation of gRPC. CWE-178
• CVE-2026-83612 xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and… CWE-178
• CVE-2026-73270 Improper Handling of Case Sensitivity vulnerability in Erlang/OTP inets httpd allows a… CWE-178
• CVE-2026-82726 Permissive Regular Expression vulnerability in ash-project ash_phoenix lets a remote… CWE-178
• CVE-2026-78959 Improper handling of case sensitivity in FileSystem in Google Chrome prior to… CWE-178