{"id":"GHSA-mcx4-f5f5-4859","aliases":["BIT-symfony-2020-5255","CVE-2020-5255"],"title":"Prevent cache poisoning via a Response Content-Type header in Symfony","description":"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the issue.","severity":"low","score":2.6,"published":"2020-03-30T20:09:16.000Z","modified":"2026-09-10T03:48:29.528Z","withdrawn":false,"knownExploited":false,"affected":[{"ecosystem":"Packagist","name":"symfony/http-foundation","ranges":[{"events":[{"introduced":"4.4.0"},{"fixed":"4.4.7"}],"type":"ECOSYSTEM"}],"versions":["v4.4.0","v4.4.1","v4.4.2","v4.4.3","v4.4.4","v4.4.5","v4.4.6"],"fixed":["4.4.7"]},{"ecosystem":"Packagist","name":"symfony/http-foundation","ranges":[{"events":[{"introduced":"5.0.0"},{"fixed":"5.0.7"}],"type":"ECOSYSTEM"}],"versions":["v5.0.0","v5.0.1","v5.0.2","v5.0.3","v5.0.4","v5.0.5","v5.0.6"],"fixed":["5.0.7"]},{"ecosystem":"Packagist","name":"symfony/symfony","ranges":[{"events":[{"introduced":"4.4.0"},{"fixed":"4.4.7"}],"type":"ECOSYSTEM"}],"versions":["v4.4.0","v4.4.1","v4.4.2","v4.4.3","v4.4.4","v4.4.5","v4.4.6"],"fixed":["4.4.7"]},{"ecosystem":"Packagist","name":"symfony/symfony","ranges":[{"events":[{"introduced":"5.0.0"},{"fixed":"5.0.7"}],"type":"ECOSYSTEM"}],"versions":["v5.0.0","v5.0.1","v5.0.2","v5.0.3","v5.0.4","v5.0.5","v5.0.6"],"fixed":["5.0.7"]}],"references":["https://github.com/symfony/symfony/security/advisories/GHSA-mcx4-f5f5-4859","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"],"sources":[{"name":"OSV","id":"GHSA-mcx4-f5f5-4859","modified":"2026-09-10T03:48:29.528668079Z","url":"https://osv.dev/vulnerability/GHSA-mcx4-f5f5-4859"}],"assessments":[{"source":"OSV","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:L","score":2.6}]}