{
  "canonical_id": "aspnet-core--CVE-2020-1045",
  "system_id": "aspnet-core",
  "display_name": "ASP.NET Core",
  "category": "frameworks",
  "advisory_mode": "core",
  "title": "CVE-2020-1045",
  "summary": "<p>A security feature bypass vulnerability exists in the way Microsoft ASP.NET Core parses encoded cookie names.</p>\n<p>The ASP.NET Core cookie parser decodes entire cookie strings which could allow a malicious attacker to set a second cookie with the name being percent encoded.</p>\n<p>The security update addresses the vulnerability by fixing the way the ASP.NET Core cookie parser handles encoded names.</p>",
  "published_at": "2020-09-11T17:15:18.307",
  "updated_at": "2026-02-23T18:23:07.950",
  "severity": "high",
  "cvss_score": 7.5,
  "exploit_status": "unknown",
  "source_confidence": "official",
  "official_source_url": "https://access.redhat.com/errata/RHSA-2020:3699",
  "secondary_source_urls": [
    "https://github.com/dotnet/core/blob/main/release-notes/3.1/3.1.8/3.1.8.md#changes-in-318",
    "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5LN2FUVBSVPGK7AU3NMLO3YR6CGONQPB/",
    "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ASICXQXS4M7MTAF6SGQMCLCA63DLCUT3/",
    "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1045",
    "https://security.snyk.io/vuln/SNYK-RHEL8-DOTNET-1439600"
  ],
  "aliases": [
    "CVE-2020-1045"
  ],
  "cve_ids": [
    "CVE-2020-1045"
  ],
  "ghsa_ids": [],
  "osv_ids": [],
  "affected_versions": [],
  "fixed_versions": [],
  "package_name": null,
  "render_markdown": false,
  "case_path": null,
  "secure_code_topics": [
    "authz-server-side-recheck",
    "xss-output-encoding",
    "file-upload-validation",
    "token-cookie-storage"
  ],
  "status": "triage",
  "triage_reasons": [
    "missing affected/fixed version details"
  ],
  "verification_status": "triage-manual",
  "verification_mode": "synthetic",
  "last_verified_at": null,
  "last_run_id": null,
  "evidence_bundle": null,
  "historical_status": null,
  "latest_status": null,
  "browser_evidence": {
    "required": false,
    "present": false,
    "refs": []
  },
  "repro_profile_id": "xss-generic",
  "artifact_mode": "synthetic",
  "blocked_reason": null,
  "metadata": {
    "source_names": [
      "NVD ASP.NET Core"
    ],
    "source_kinds": [
      "nvd-search"
    ],
    "candidate_count": 1
  }
}