CVE-2025-48877

Discourse vulnerable to auto-executing of third-party code in embedded CodePen iframe

State: Published
Severity: 8.1 High
Published: Jun 9, 2025
Updated: Jun 9, 2025
Reserved: May 27, 2025

Description

Discourse is an open-source discussion platform. Prior to version 3.4.4 of the `stable` branch, version 3.5.0.beta5 of the `beta` branch, and version 3.5.0.beta6-dev of the `tests-passed` branch, Codepen is present in the default `allowed_iframes` site setting, and it can potentially auto-run arbitrary JS in the iframe scope, which is unintended. This issue is patched in version 3.4.4 of the `stable` branch, version 3.5.0.beta5 of the `beta` branch, and version 3.5.0.beta6-dev of the `tests-passed` branch. As a workaround, the Codepen prefix can be removed from a site's `allowed_iframes`.

Scores

CVSS	Score	Vector	Source
4.0	8.1 High	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U	GitHub_M

Weaknesses

CWE-1038 Insecure Automated Optimizations

Affected Products

Product	Versions
discoursediscourse	< 3.4.4Affected < 3.5.0.beta5Affected < 3.5.0.beta6-devAffected

References

https://github.com/discourse/discourse/security/advisories/GHSA-cm93-6m2m-cjcv

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