CVE-2026-27166 (GCVE-0-2026-27166)
Vulnerability from cvelistv5 – Published: 2026-03-19 20:29 – Updated: 2026-03-21 03:31
VLAI
EPSS
VEX
Title
Discourse vulnerable to HTML injection via prohibited iframe URLs
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.
Severity
4.1 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-03-21 03:31 UTC
CWE
- CWE-80 - Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://github.com/discourse/discourse/security/a… | x_refsource_CONFIRM |
| https://github.com/discourse/discourse/commit/c47… | x_refsource_MISC |
Impacted products
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},
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"lastModified": "2026-06-17T10:26:46.800",
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Browse all ATT&CK techniques and the vulnerabilities related to each.
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