{
  "canonical_id": "symfony--CVE-2020-5255",
  "system_id": "symfony",
  "display_name": "Symfony",
  "category": "frameworks",
  "advisory_mode": "core",
  "title": "Prevent cache poisoning via a Response Content-Type header in Symfony",
  "summary": "Description\n-----------\n\nWhen a `Response` does not contain a `Content-Type` header, Symfony falls back to the format defined in the `Accept` header of the request, leading to a possible mismatch between the response's content and `Content-Type` header. When the response is cached, this can lead to a corrupted cache where the cached format is not the right one.\n\nResolution\n----------\n\nSymfony does not use the `Accept` header anymore to guess the `Content-Type`.\n\nThe patch for this issue is available [here](https://github.com/symfony/symfony/commit/dca343442e6a954f96a2609e7b4e9c21ed6d74e6) for the 4.4 branch.\n\nCredits\n-------\n\nI would like to thank Xavier Lacot from JoliCode for reporting & Yonel Ceruto and Tobias Schultze for fixing the issue.",
  "published_at": "2020-03-30T20:09:16Z",
  "updated_at": "2026-03-13T22:01:08.748385Z",
  "severity": "low",
  "cvss_score": 3.1,
  "exploit_status": "unknown",
  "source_confidence": "official",
  "official_source_url": "https://github.com/symfony/symfony/security/advisories/GHSA-mcx4-f5f5-4859",
  "secondary_source_urls": [
    "https://nvd.nist.gov/vuln/detail/CVE-2020-5255",
    "https://github.com/symfony/symfony/commit/dca343442e6a954f96a2609e7b4e9c21ed6d74e6",
    "https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/http-foundation/CVE-2020-5255.yaml",
    "https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/symfony/CVE-2020-5255.yaml",
    "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/C36JLPHUPKDFAX6D5WYFC4ALO2K7RDUQ",
    "https://symfony.com/blog/cve-2020-5255-prevent-cache-poisoning-via-a-response-content-type-header",
    "https://symfony.com/cve-2020-5255"
  ],
  "aliases": [
    "BIT-symfony-2020-5255",
    "CVE-2020-5255",
    "GHSA-mcx4-f5f5-4859"
  ],
  "cve_ids": [
    "CVE-2020-5255"
  ],
  "ghsa_ids": [
    "GHSA-mcx4-f5f5-4859"
  ],
  "osv_ids": [
    "GHSA-mcx4-f5f5-4859"
  ],
  "affected_versions": [
    "v4.4.0",
    "v4.4.1",
    "v4.4.2",
    "v4.4.3",
    "v4.4.4",
    "v4.4.5",
    "v4.4.6",
    "v5.0.0",
    "v5.0.1",
    "v5.0.2",
    "v5.0.3",
    "v5.0.4",
    "v5.0.5",
    "v5.0.6",
    "introduced=4.4.0, fixed<4.4.7",
    "introduced=5.0.0, fixed<5.0.7"
  ],
  "fixed_versions": [
    "4.4.7",
    "5.0.7"
  ],
  "package_name": "symfony/symfony",
  "render_markdown": true,
  "case_path": "07-framework-security/frameworks/symfony/cases/symfony-cve-2020-5255.md",
  "secure_code_topics": [
    "xss-output-encoding",
    "authz-server-side-recheck",
    "path-traversal-guard"
  ],
  "status": "generated",
  "triage_reasons": [],
  "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": [
      "OSV Symfony"
    ],
    "source_kinds": [
      "osv-batch"
    ],
    "candidate_count": 1
  }
}