Open edX Platform enables the authoring and delivery of online learning at any scale. The HTML sanitizer clean_thread_html_body() used for discussion notification emails fails to remove <style> tags from user-generated discussion post content. This content is rendered with Django's |safe template filter in email notification templates, allowing any enrolled student to inject arbitrary CSS into email notifications sent to other users. This enables email tracking (IP address disclosure), content spoofing, and phishing attacks. This vulnerability is fixed with commit cddc25cd791bb78f76833896e4778f668861df12.
Fix
Patch, vendor advisory and mitigation references on NVD 3
- https://github.com/openedx/openedx-platform/commit/cddc25cd791bb78f76833896e4778f668861df12 Patch
- https://github.com/openedx/openedx-platform/security/advisories/GHSA-4xv3-5j4x-q8g4 Exploit, Vendor Advisory
- https://github.com/openedx/openedx-platform/security/advisories/GHSA-4xv3-5j4x-q8g4 Exploit, Vendor Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 5.4 · openedxNVD modified 2026-10-26 18:10
Affected (CPE criteria) 1
cpe:2.3:a:openedx:openedx:*:*:*:*:*:*:*:*
References 3
- https://github.com/openedx/openedx-platform/commit/cddc25cd791bb78f76833896e4778f668861df12 Patch
- https://github.com/openedx/openedx-platform/security/advisories/GHSA-4xv3-5j4x-q8g4 Exploit, Vendor Advisory
- https://github.com/openedx/openedx-platform/security/advisories/GHSA-4xv3-5j4x-q8g4 Exploit, Vendor Advisory