VULNERABILITY INTELLIGENCE

CVE-2026-72721

CVSS score5.3 MEDIUM
EPSS probability0.58%
CISA KEVNot currently listed
Published2026-08-10
Last modified2026-09-08
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Description

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.

Weakness classification

  • security-advisories@github.com: CWE-178

Primary references