PT-2026-69861 · Discourse · Discourse

CVE-2026-72721

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Published

2026-08-10

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Updated

2026-08-17

CVSS v3.1

5.3

Medium

VectorAV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Name of the Vulnerable Software and Affected Versions Discourse versions prior to 2026.1.6 Discourse versions prior to 2026.5.2 Discourse versions prior to 2026.6.1 Discourse versions prior to 2026.7.0
Description Onebox::DomainChecker.is blocked? performs a case-sensitive comparison between hostnames and the entries in SiteSetting.blocked onebox domains. This allows an attacker to bypass configured Onebox domain restrictions by altering the character casing of a redirect target hostname.
Recommendations Update to version 2026.1.6 Update to version 2026.5.2 Update to version 2026.6.1 Update to version 2026.7.0

Exploit

Fix

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dbugs@ptsecurity.com

Weakness Enumeration

CWE-178

Related Identifiers

BIT-DISCOURSE-2026-72721
CVE-2026-72721
GHSA-3X7X-24RQ-H5J6

Affected Products

Discourse