django CMS: Stored XSS in edit-mode plugin exception rendering

{
  "id": "2d60e950aec1a38dc5119a8e4e5987c7cbb495933a3e8a9c52e68ead14e7f1a5",
  "url": "https://osv.dev/vulnerability/CVE-2026-75526",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "django CMS: Stored XSS in edit-mode plugin exception rendering",
    "summary": "django CMS is an easy-to-use and developer-friendly enterprise content management system powered by Django. From 5.0.8 until 5.0.9, ContentRenderer.render_placeholder in cms/plugin_rendering.py can pass stored, attacker-controlled values to ContentRenderer.render_exception when plugin rendering fails in edit mode. Values from get_short_description(), the exception message, the placeholder, or placeholder.source are interpolated into a cms-rendering-exception heading and later returned through mark_safe. Because the heading is not escaped, stored HTML executes in an editor’s browser, and settings.DEBUG does not prevent the custom heading from rendering. The fix uses format_html to escape the message before safe placeholder output is returned. This issue is fixed in versions 5.0.9.",
    "evidence": "osv:CVE-2026-75526",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-75526",
      "aliases": [
        "CVE-2026-75526",
        "GHSA-hvq6-2r72-p2x7",
        "PYSEC-2026-3825"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/django-cms/django-cms",
              "type": "GIT",
              "events": [
                {
                  "introduced": "6da7840759c2b345a0e2fd4e796be001e681c6a4"
                },
                {
                  "fixed": "d7eeb6526bd757cfcdf28122066f39803990c5e4"
                },
                {
                  "fixed": "b56a568844ff3702495945f73a31d0868285bf88"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "5.0.8"
                      },
                      {
                        "fixed": "5.0.9"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "b56a568844ff3702495945f73a31d0868285bf88"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "d7eeb6526bd757cfcdf28122066f39803990c5e4"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "5.0.9"
                  }
                ]
              }
            }
          ],
          "versions": [
            "5.0.8"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-75526.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:50.361137881Z",
      "provider": "osv",
      "references": [
        "https://github.com/django-cms/django-cms/releases/tag/5.0.9",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/75xxx/CVE-2026-75526.json",
        "https://github.com/django-cms/django-cms/security/advisories/GHSA-hvq6-2r72-p2x7",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-75526",
        "https://github.com/django-cms/django-cms/commit/b56a568844ff3702495945f73a31d0868285bf88",
        "https://github.com/django-cms/django-cms/pull/8711"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-79"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/75xxx/CVE-2026-75526.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-75526",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 518919,
  "published_at": "2026-08-20T18:11:10.22+00:00"
}