Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, sites using wildcard patterns in the allowed_iframes setting could accept a crafted iframe URL whose allowlisted suffix appeared after a URL authority separator. The wildcard origin check matched the allowed domain text, while browser URL parsing selected a different attacker-controlled origin. A user with posting privileges could exploit the flaw through a post or a Onebox oEmbed response and cause an attacker-controlled iframe to be rendered independently of the allowlisted domain. Successful exploitation requires a site-configured wildcard iframe pattern and the ability to create a post or trigger an oEmbed request for an attacker-controlled URL. This issue is fixed in versions 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0.
Metrics
Affected Vendors & Products
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History
Tue, 29 Sep 2026 03:30:00 +0000
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ssvc
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Thu, 24 Sep 2026 20:00:00 +0000
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Discourse
Discourse discourse |
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Discourse
Discourse discourse |
Thu, 24 Sep 2026 17:00:00 +0000
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| Description | Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, sites using wildcard patterns in the allowed_iframes setting could accept a crafted iframe URL whose allowlisted suffix appeared after a URL authority separator. The wildcard origin check matched the allowed domain text, while browser URL parsing selected a different attacker-controlled origin. A user with posting privileges could exploit the flaw through a post or a Onebox oEmbed response and cause an attacker-controlled iframe to be rendered independently of the allowlisted domain. Successful exploitation requires a site-configured wildcard iframe pattern and the ability to create a post or trigger an oEmbed request for an attacker-controlled URL. This issue is fixed in versions 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0. | |
| Title | Discourse: Wildcard iframe origin allowlist bypass via authority separators | |
| Weaknesses | CWE-346 | |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: GitHub_M
Published: 2026-09-24T16:57:43.082Z
Updated: 2026-09-29T02:57:34.925Z
Reserved: 2026-09-14T19:36:48.844Z
Link: CVE-2026-91132
Updated: 2026-09-29T02:57:28.470Z
Status : Deferred
Published: 2026-09-24T17:17:08.723
Modified: 2026-09-29T03:17:21.457
Link: CVE-2026-91132
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