CVE-2026-27166
4.1
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:N
Summary
Discourse is an open source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1 and 2026.1.2, insufficient cleanup in the default Codepen allowed iframes value allows an attacker to trick a user into changing the URL of the main page. This issue has been fixed in versions 2026.3.0-latest.1, 2026.2.1 and 2026.1.2. To workaround this issue, remove Codepen from the list of allowed iframes.
Affected Software
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| discourse | discourse | < 2026.3.0-latest.1 | affected |
| discourse | discourse | >= 2026.2.0-latest, < 2026.2.1 | affected |
| discourse | discourse | >= 2026.1.0-latest, < 2026.1.2 | affected |
Weaknesses
- CWE-80: CWE-80: Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)
ADP Enrichment
CISA ADP Vulnrichment
- SSVC:
- Exploitation: none
- Automatable: no
- Technical Impact: partial
References
- https://github.com/discourse/discourse/security/advisories/GHSA-h653-cq78-vjj2
- https://github.com/discourse/discourse/commit/c4762a4fac2f61f52f325396b11d3aeb955ea925
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