5.4

CVE-2026-42857

Exploit

Open edX Platform: Stored CSS Injection in Email Notifications via Incomplete HTML Sanitization

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.
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Openedx ≫ Openedx Version < 2026-04-24
Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.21% 0.111
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
nvd@nist.gov 5.4 2.3 2.7
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
security-advisories@github.com 4.6 2.1 2.5
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N
CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

https://github.com/openedx/openedx-platform/commit/cddc25cd791bb78f76833896e4778f668861df12
Patch
https://github.com/openedx/openedx-platform/security/advisories/GHSA-4xv3-5j4x-q8g4
Vendor Advisory
Exploit