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

{
  "id": "c4871c1adf3115f687fb9285250f00ae8115ca8b47027377c65919ee055bbd59",
  "url": "https://osv.dev/vulnerability/CVE-2026-85271",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Open edX Platform: Stored CSS Injection in Email Digest Notifications via Unsanitized Thread Title (incomplete patch of CVE-2026-42857)",
    "summary": "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.",
    "evidence": "osv:CVE-2026-85271",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-85271",
      "aliases": [
        "CVE-2026-85271",
        "GHSA-rv5w-f4r5-h77g"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/openedx/openedx-platform",
              "type": "GIT",
              "events": [
                {
                  "introduced": "142bb24065fa23eeaf9806a560762aa00013f296"
                },
                {
                  "fixed": "2af03d21b4142e53e375c7f3699b313e92ec5121"
                },
                {
                  "fixed": "52f2b3bb3e6fac2601c29e8f926c81498d20bb0b"
                },
                {
                  "fixed": "5eae6e51a8797cd3b87cc132f5de73d52561c4d7"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": ">= release/redwood.1, < release/ulmo.4"
                      },
                      {
                        "last_affected": ">= release/redwood.1, < release/ulmo.4"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandaloneSingleVersion"
                  },
                  {
                    "range": [
                      {
                        "fixed": "2af03d21b4142e53e375c7f3699b313e92ec5121"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "52f2b3bb3e6fac2601c29e8f926c81498d20bb0b"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "5eae6e51a8797cd3b87cc132f5de73d52561c4d7"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            ">= release/redwood.1, < release/ulmo.4"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-85271.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:21.712055681Z",
      "provider": "osv",
      "references": [
        "https://github.com/openedx/openedx-platform/releases/tag/release/ulmo.4",
        "https://github.com/openedx/openedx-platform/releases/tag/release/verawood.1",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/85xxx/CVE-2026-85271.json",
        "https://github.com/openedx/openedx-platform/security/advisories/GHSA-rv5w-f4r5-h77g",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-85271",
        "https://github.com/openedx/openedx-platform/commit/2af03d21b4142e53e375c7f3699b313e92ec5121",
        "https://github.com/openedx/openedx-platform/commit/52f2b3bb3e6fac2601c29e8f926c81498d20bb0b",
        "https://github.com/openedx/openedx-platform/commit/5eae6e51a8797cd3b87cc132f5de73d52561c4d7"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-79"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/85xxx/CVE-2026-85271.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-85271",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 487727,
  "published_at": "2026-09-18T20:38:40.422+00:00"
}