{"action":"Upgrade typo3/cms-core to 10.4.14 or later.","affected":[{"fixed":"10.4.14","introduced":"10.0.0"},{"fixed":"11.1.1","introduced":"11.0.0"}],"component":"typo3/cms-core","cve_ids":["CVE-2021-21340"],"ecosystem":"Packagist","epss":0.00872,"exploited":false,"fixed_versions":["10.4.14","11.1.1"],"ghsa_id":"GHSA-fjh3-g8gq-9q92","id":"tcs_01M5KF1VR1ZW4TMBGPT2E5909T","modified_at":"2026-07-08T06:28:00.165150552Z","published_at":"2021-03-23T01:53:47Z","references":["https://osv.dev/vulnerability/GHSA-fjh3-g8gq-9q92","https://github.com/TYPO3/TYPO3.CMS/security/advisories/GHSA-fjh3-g8gq-9q92","https://nvd.nist.gov/vuln/detail/CVE-2021-21340","https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms-core/CVE-2021-21340.yaml","https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms/CVE-2021-21340.yaml","https://packagist.org/packages/typo3/cms-backend","https://typo3.org/security/advisory/typo3-core-sa-2021-007"],"severity":{"label":"medium","score":5.4},"sources":[{"source":"osv","source_id":"GHSA-fjh3-g8gq-9q92#Packagist/typo3/cms-core","url":"https://osv.dev/vulnerability/GHSA-fjh3-g8gq-9q92"}],"summary":"Cross-Site Scripting in Content Preview"}