CVE-2026-109399

{
  "etk_id": "ETK-2026-1375",
  "cve_id": "CVE-2026-109399",
  "display_id": "CVE-2026-109399",
  "ghsa_id": null,
  "euvd_id": "EUVD-2026-97496",
  "status": "published",
  "anchor_state": "anchored",
  "title": "CMS certificate validation flaw in SWUpdate",
  "summary": "SWUpdate through 2026.05.1 can incorrectly accept CMS-signed updates because embedded certificates influence certificate-chain validation. An attacker with a signing key from another intermediate under the same trusted root could cause installation of a malicious update.",
  "mitigation": "Limit update ingestion to authenticated, trusted delivery paths and avoid installing update artifacts from untrusted sources. Where supported, pin acceptable signing certificates or intermediates and review trusted-root configuration; no fixed version is recorded.",
  "vendor": "sbabic",
  "product": "swupdate",
  "affected": [
    {
      "affected_notes": [],
      "affected_ranges": [
        ">= 0, <= 2026.05.1"
      ],
      "ecosystem": null,
      "fixed_versions": [],
      "package_name": "swupdate",
      "purl": null
    }
  ],
  "cwes": [
    295
  ],
  "cvss_score": 9.2,
  "cvss_src": "cna_vendor",
  "cvss_vector": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
  "epss_score": 0.0021,
  "epss_percentile": 0.1057,
  "epss_asof": "2026-10-20",
  "automation": "contextual",
  "check": false,
  "check_confidence_basis": null,
  "exploit": false,
  "pipeline_minutes": 14.774541133333333,
  "t0_at": "2026-10-12T15:16:44.440000+00:00",
  "signals": {
    "trigger_signal": {
      "at": "2026-10-12T15:16:44.440000+00:00",
      "days": 0,
      "is_lower_bound": false,
      "measured_at": "2026-10-12T15:16:44.440000+00:00",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-109399"
    }
  }
}