Home/CVE/Discourse is an open-source discussion platform. Prior to version 3.4.4 of the `stable` branch, version 3.5.0.beta5 of t
CVE

CVE-2025-48877

Discourse is an open-source discussion platform. Prior to version 3.4.4 of the `stable` branch, version 3.5.0.beta5 of t

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.

CRITICAL · CVSS 9.8 EPSS 0.0069
Schedule remediation
  • SSVC automatable: yes - attacks can be scripted at scale
  • CVSS base score ≥ 7.0
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-1038Insecure Automated Optimizations
▤

Affected Products & Versions

3
discourse< 3.4.4
discourse< 3.5.0
discourseall versions
▣

Scoring & Timeline

9.8
CRITICAL · CVSS v3.1 · security-advisories@github.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD09 Jun 2025 · 01:15 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
yes
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
🔗

References & Sources

1
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://github.com/discourse/discourse/security/advisories/GHSA-cm93-6m2m-cjcvVendor Advisory
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