PT-2026-26425 · Discourse · Discourse

Davidtaylorhq · Published 2026-03-19 · Updated 2026-03-19 · CVE-2026-33393

Mitre

CVSS v3.1

4.3

Medium

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

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, the allowed spam host domains check used String#end with? without domain boundary validation, allowing domains like attacker-example.com to bypass spam protection when example.com was allowlisted. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 require exact match or proper subdomain match (preceded by .) to prevent suffix-based bypass of newuser spam host threshold. No known workarounds are available.

Fix

Improper Access Control

Weakness Enumeration

CWE-284

Related Identifiers

CVE-2026-33393

Affected Products

Discourse

References · 5

• https://nvd.nist.gov/vuln/detail/CVE-2026-33393 · Security Note
• https://github.com/discourse/discourse/commit/d8467b9fbb3d9ed6047b4e508d3fef88a37b8a02 · Note
• https://github.com/discourse/discourse/commit/80b19c15fe9c7bc890d1a54f454c8446312ac6d2 · Note
• https://github.com/discourse/discourse/commit/f99099cfbc6b76fe39d6fa2daa48efd69497fb8e · Note
• https://github.com/discourse/discourse/security/advisories/GHSA-95r5-p6qr-hgw6 · Note