{"id":"CVE-2020-5255","aliases":["BIT-symfony-2020-5255","DEBIAN-CVE-2020-5255","EUVD-2020-0351","GHSA-mcx4-f5f5-4859"],"status":"published","title":"Prevent cache poisoning via a Response Content-Type header","description":"In Symfony before versions 4.4.7 and 5.0.7, when a `Response` does not contain a `Content-Type` header, affected versions of Symfony can fallback to the format defined in the `Accept` header of the request, leading to a possible mismatch between the response\u0026#39;s content and `Content-Type` header. When the response is cached, this can prevent the use of the website by other users. This has been patched in versions 4.4.7 and 5.0.7.","severity":{"version":"3.1","score":2.6,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:L","level":"low","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.01297,"percentile":0.70587,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-20","CWE-435"],"published":"2020-03-30T19:30:15Z","modified":"2026-10-26T12:02:04Z","fixes":[{"ecosystem":"Packagist","package":"symfony/http-foundation","fixed_in":["4.4.7","5.0.7"],"sources":["ghsa","osv"]},{"ecosystem":"Packagist","package":"symfony/symfony","fixed_in":["4.4.7","5.0.7"],"sources":["ghsa","osv"]},{"ecosystem":"Bitnami","package":"symfony","fixed_in":["4.4.7","5.0.7"],"sources":["osv"]},{"ecosystem":"Debian:12","package":"symfony","fixed_in":["4.4.8-1"],"sources":["osv"]},{"ecosystem":"Debian:13","package":"symfony","fixed_in":["4.4.8-1"],"sources":["osv"]},{"ecosystem":"Debian:14","package":"symfony","fixed_in":["4.4.8-1"],"sources":["osv"]}],"affected":[{"source":"ghsa","ecosystem":"Packagist","package":"symfony/http-foundation","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.4.0"},{"fixed":"4.4.7"}]}]},{"source":"ghsa","ecosystem":"Packagist","package":"symfony/http-foundation","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.0.0"},{"fixed":"5.0.7"}]}]},{"source":"ghsa","ecosystem":"Packagist","package":"symfony/symfony","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.4.0"},{"fixed":"4.4.7"}]}]},{"source":"ghsa","ecosystem":"Packagist","package":"symfony/symfony","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.0.0"},{"fixed":"5.0.7"}]}]},{"source":"osv","ecosystem":"Bitnami","package":"symfony","ranges":[{"type":"SEMVER","events":[{"introduced":"4.4.0"},{"fixed":"4.4.7"},{"introduced":"5.0.0"},{"fixed":"5.0.7"}]}]},{"source":"osv","ecosystem":"Debian:12","package":"symfony","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.4.8-1"}]}]},{"source":"osv","ecosystem":"Debian:13","package":"symfony","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.4.8-1"}]}]},{"source":"osv","ecosystem":"Debian:14","package":"symfony","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.4.8-1"}]}]},{"source":"osv","ecosystem":"Packagist","package":"symfony/http-foundation","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.4.0"},{"fixed":"4.4.7"}]}],"versions":["v4.4.0","v4.4.1","v4.4.2","v4.4.3","v4.4.4","v4.4.5","v4.4.6"]},{"source":"osv","ecosystem":"Packagist","package":"symfony/http-foundation","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.0.0"},{"fixed":"5.0.7"}]}],"versions":["v5.0.0","v5.0.1","v5.0.2","v5.0.3","v5.0.4","v5.0.5","v5.0.6"]},{"source":"osv","ecosystem":"Packagist","package":"symfony/symfony","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.4.0"},{"fixed":"4.4.7"}]}],"versions":["v4.4.0","v4.4.1","v4.4.2","v4.4.3","v4.4.4","v4.4.5","v4.4.6"]},{"source":"osv","ecosystem":"Packagist","package":"symfony/symfony","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.0.0"},{"fixed":"5.0.7"}]}],"versions":["v5.0.0","v5.0.1","v5.0.2","v5.0.3","v5.0.4","v5.0.5","v5.0.6"]}],"products":[{"vendor":"sensiolabs","product":"symfony"},{"vendor":"symfony","product":"symfony"}],"references":[{"url":"https://github.com/symfony/symfony/security/advisories/GHSA-mcx4-f5f5-4859","tags":["x_refsource_CONFIRM","x_transferred","Third Party Advisory","web","advisory"]},{"url":"https://github.com/symfony/symfony/commit/dca343442e6a954f96a2609e7b4e9c21ed6d74e6","tags":["x_refsource_MISC","x_transferred","Patch","Third Party Advisory","web","fix"]},{"url":"https://symfony.com/blog/cve-2020-5255-prevent-cache-poisoning-via-a-response-content-type-header","tags":["x_refsource_MISC","x_transferred","Third Party Advisory","web","advisory"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/C36JLPHUPKDFAX6D5WYFC4ALO2K7RDUQ/","tags":["vendor-advisory","x_refsource_FEDORA","x_transferred","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2020-5255","tags":["advisory"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/C36JLPHUPKDFAX6D5WYFC4ALO2K7RDUQ/"},{"url":"https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/http-foundation/CVE-2020-5255.yaml","tags":["web"]},{"url":"https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/symfony/CVE-2020-5255.yaml","tags":["web"]},{"url":"https://symfony.com/cve-2020-5255","tags":["web"]},{"url":"https://github.com/advisories/GHSA-mcx4-f5f5-4859"},{"url":"https://security-tracker.debian.org/tracker/CVE-2020-5255","tags":["advisory"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/C36JLPHUPKDFAX6D5WYFC4ALO2K7RDUQ","tags":["web"]}],"sources":{"cve":[{"id":"CVE-2020-5255","title":"Prevent cache poisoning via a Response Content-Type header","description":"In Symfony before versions 4.4.7 and 5.0.7, when a `Response` does not contain a `Content-Type` header, affected versions of Symfony can fallback to the format defined in the `Accept` header of the request, leading to a possible mismatch between the response\u0026#39;s content and `Content-Type` header. When the response is cached, this can prevent the use of the website by other users. This has been patched in versions 4.4.7 and 5.0.7.","status":"published","published":"2020-03-30T19:30:15Z","modified":"2024-08-04T08:22:09.086Z","cvss":[{"version":"3.1","score":2.6,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:L","level":"low","assessor":"cna"}],"cwes":["CWE-435"],"updated_at":"2026-11-02T14:35:47.56691Z"}],"euvd":[{"id":"EUVD-2020-0351","description":"In Symfony before versions 4.4.7 and 5.0.7, when a `Response` does not contain a `Content-Type` header, affected versions of Symfony can fallback to the format defined in the `Accept` header of the request, leading to a possible mismatch between the response\u0026#39;s content and `Content-Type` header. When the response is cached, this can prevent the use of the website by other users. This has been patched in versions 4.4.7 and 5.0.7.","status":"published","published":"2020-03-30T19:30:15Z","modified":"2024-08-04T08:22:09Z","cvss":[{"version":"3.1","score":2.6,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:L","level":"low"}],"updated_at":"2026-11-03T03:08:07.28588Z"}],"ghsa":[{"id":"GHSA-mcx4-f5f5-4859","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 \u0026 Yonel Ceruto and Tobias Schultze for fixing the issue.","status":"published","published":"2020-03-30T20:09:16Z","modified":"2024-02-05T11:10:43Z","cvss":[{"version":"3.1","score":2.6,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:L","level":"low"}],"cwes":["CWE-435"],"updated_at":"2026-11-02T14:37:35.293818Z"}],"nvd":[{"id":"CVE-2020-5255","description":"In Symfony before versions 4.4.7 and 5.0.7, when a `Response` does not contain a `Content-Type` header, affected versions of Symfony can fallback to the format defined in the `Accept` header of the request, leading to a possible mismatch between the response\u0026#39;s content and `Content-Type` header. When the response is cached, this can prevent the use of the website by other users. This has been patched in versions 4.4.7 and 5.0.7.","status":"published","published":"2020-03-30T20:15:19.57Z","modified":"2026-06-17T03:21:08.493Z","cvss":[{"version":"3.1","score":2.6,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:L","level":"low","assessor":"secondary"},{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L","level":"medium","assessor":"primary"},{"version":"2.0","score":4,"vector":"AV:N/AC:L/Au:S/C:N/I:N/A:P","level":"medium","assessor":"primary"}],"cwes":["CWE-435","CWE-20"],"updated_at":"2026-11-02T14:05:56.580228Z"}],"osv":[{"id":"CVE-2020-5255","description":"In Symfony before versions 4.4.7 and 5.0.7, when a `Response` does not contain a `Content-Type` header, affected versions of Symfony can fallback to the format defined in the `Accept` header of the request, leading to a possible mismatch between the response\u0026#39;s content and `Content-Type` header. When the response is cached, this can prevent the use of the website by other users. This has been patched in versions 4.4.7 and 5.0.7.","status":"published","published":"2020-03-30T20:15:19.57Z","modified":"2026-10-24T10:50:39.317914392Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"updated_at":"2026-11-02T15:44:16.936975Z"},{"id":"DEBIAN-CVE-2020-5255","description":"In Symfony before versions 4.4.7 and 5.0.7, when a `Response` does not contain a `Content-Type` header, affected versions of Symfony can fallback to the format defined in the `Accept` header of the request, leading to a possible mismatch between the response\u0026#39;s content and `Content-Type` header. When the response is cached, this can prevent the use of the website by other users. This has been patched in versions 4.4.7 and 5.0.7.","status":"published","published":"2020-03-30T20:15:19.57Z","modified":"2026-10-26T12:02:04.568643893Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"updated_at":"2026-11-02T15:45:34.019707Z"},{"id":"GHSA-mcx4-f5f5-4859","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 \u0026 Yonel Ceruto and Tobias Schultze for fixing the issue.","status":"published","published":"2020-03-30T20:09:16Z","modified":"2026-09-10T03:48:29.528668079Z","cvss":[{"version":"3.1","score":2.6,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:L","level":"low"}],"cwes":["CWE-435"],"updated_at":"2026-11-02T15:46:51.811331Z"},{"id":"BIT-symfony-2020-5255","description":"In Symfony before versions 4.4.7 and 5.0.7, when a `Response` does not contain a `Content-Type` header, affected versions of Symfony can fallback to the format defined in the `Accept` header of the request, leading to a possible mismatch between the response\u0026#39;s content and `Content-Type` header. When the response is cached, this can prevent the use of the website by other users. This has been patched in versions 4.4.7 and 5.0.7.","status":"published","published":"2024-03-06T11:08:47.47Z","modified":"2024-03-06T11:25:28.861Z","updated_at":"2026-11-02T15:28:35.51001Z"}]}}