CVE-2026-72721

MediumCVSS 5.3/10Last modified Sep 8, 2026

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.

Metrics

CVSS 3.1 5.3/10CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Weakness enumeration

CWE-178

Affected software

No affected versions have been published.

Timeline

Published
Aug 10, 2026
Last modified
Sep 8, 2026
NVD status
Deferred

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CVE-2026-72721: Medium severity, CVSS 5.3 | Vulnix