{"id":"CVE-2021-35955","aliases":["GHSA-hr3h-x6gq-rqcp"],"url":"https://o3.security/vulnerability/CVE-2021-35955","summary":"Cross site scripting via HTML attributes in the back end","details":"Contao >=4.0.0 allows backend XSS via HTML attributes to an HTML field. Fixed in 4.4.56, 4.9.18, 4.11.7.","published":"2021-08-12T15:15:07.960Z","modified":"2026-08-07T16:57:27.203127Z","cvss":{"score":4.8,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Packagist","name":"contao/core-bundle","fixedVersion":"4.4.56"},{"ecosystem":"Packagist","name":"contao/contao","fixedVersion":"4.4.56"},{"ecosystem":"Packagist","name":"contao/contao","fixedVersion":"4.9.18"},{"ecosystem":"Packagist","name":"contao/contao","fixedVersion":"4.11.7"},{"ecosystem":"Packagist","name":"contao/core-bundle","fixedVersion":"4.9.18"},{"ecosystem":"Packagist","name":"contao/core-bundle","fixedVersion":"4.11.7"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://contao.org/en/news/contao-4-9-16-and-4-11-5-are-available.html"},{"type":"ADVISORY","url":"https://github.com/contao/contao/security/advisories/GHSA-hr3h-x6gq-rqcp"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-07T16:57:27.203127Z"}}