CVE-2026-72721
MEDIUM
5,3
Source: [email protected]
Attack Vector: network
Attack Complexity: low
Privileges Required: none
User Interaction: none
Scope: unchanged
Confidentiality: low
Integrity: none
Availability: none
Description
AI Translation Available
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.
178
Improper Handling of Case Sensitivity
IncompleteCommon Consequences
Security Scopes Affected:
Access Control
Potential Impacts:
Bypass Protection Mechanism
Applicable Platforms
Operating Systems:
Windows, macOS
https://github.com/discourse/discourse/commit/a3e10759fef47f03d450649bb51d9e84f…
https://github.com/discourse/discourse/commit/c2eb6b0e5597d6f28f4be739b83300bc9…
https://github.com/discourse/discourse/commit/caa615c371b1696982ee11ac8f3558f0f…
https://github.com/discourse/discourse/commit/f503971d311b7b0dfdb751ee8cfd67e8c…
https://github.com/discourse/discourse/pull/42091
https://github.com/discourse/discourse/pull/42092
https://github.com/discourse/discourse/pull/42093
https://github.com/discourse/discourse/pull/42094
https://github.com/discourse/discourse/security/advisories/GHSA-3x7x-24rq-h5j6