Chromium: CVE-2026-78903 Incomplete cleanup in SiteIsolation

{
  "id": "2315ae91e381903775419be8e1f9e04cc3b562007b60745a7a7da9046009f540",
  "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-78903",
  "method": "llm",
  "payload": {
    "kind": "other",
    "title": "Chromium: CVE-2026-78903 Incomplete cleanup in SiteIsolation",
    "summary": "The announcement says Chromium addresses this vulnerability and directs readers to Google Chrome Releases for more information.",
    "evidence": "Microsoft Edge (Chromium-based) ingests Chromium, which addresses this vulnerability.",
    "products": [
      {
        "name": {
          "value": "Microsoft Edge (Chromium-based)",
          "evidence": "Microsoft Edge (Chromium-based) ingests Chromium"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "fixed_cves": [],
    "related_cves": [
      {
        "value": "CVE-2026-78903",
        "evidence": "Chromium: CVE-2026-78903 Incomplete cleanup in SiteIsolation"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "official-microsoft-security-updates",
  "document_id": 27249,
  "published_at": "2026-08-28T14:00:00+00:00"
}