{"id":"GHSA-h58v-c6rf-g9f7","aliases":["CVE-2021-35210"],"title":"Cross site scripting in the system log","titleSource":"OSV","descriptionSource":"OSV","declaredSeverity":"MODERATE","description":"### Impact\n\nIt is possible to inject code into the `tl_log` table that will be executed in the browser when the system log is called in the back end.\n\n### Patches\n\nUpdate to Contao 4.9.16 or 4.11.5.\n\n### Workarounds\n\nDisable the system log module in the back end for all users (especially admin users).\n\n### References\n\nhttps://contao.org/en/security-advisories/cross-site-scripting-in-the-system-log-2021\n\n### For more information\n\nIf you have any questions or comments about this advisory, open an issue in [contao/contao](https://github.com/contao/contao/issues/new/choose).","severity":"medium","score":6.1,"published":"2021-07-01T17:00:04.000Z","modified":"2026-09-10T03:49:06.413Z","withdrawn":false,"knownExploited":false,"affected":[{"ecosystem":"Packagist","name":"contao/core-bundle","sources":[{"name":"OSV · GHSA-h58v-c6rf-g9f7","url":"https://osv.dev/vulnerability/GHSA-h58v-c6rf-g9f7"}],"ranges":[{"events":[{"introduced":"4.5.0"},{"fixed":"4.9.16"}],"type":"ECOSYSTEM"}],"versions":["4.5.0","4.5.1","4.5.10","4.5.11","4.5.12","4.5.13","4.5.14","4.5.2","4.5.3","4.5.4","4.5.5","4.5.6","4.5.7","4.5.8","4.5.9","4.6.0","4.6.0-RC1","4.6.0-RC2","4.6.0-RC3","4.6.1","4.6.10","4.6.11","4.6.12","4.6.13","4.6.14","4.6.2","4.6.3","4.6.4","4.6.5","4.6.6","4.6.7","4.6.8","4.6.9","4.7.0","4.7.0-RC1","4.7.0-RC2","4.7.0-RC3","4.7.0-RC4","4.7.1","4.7.2","4.7.3","4.7.4","4.7.5","4.7.6","4.7.7","4.8.0","4.8.0-RC1","4.8.0-RC2","4.8.1","4.8.2","4.8.3","4.8.4","4.8.5","4.8.6","4.8.7","4.8.8","4.9.0","4.9.0-RC1","4.9.0-RC2","4.9.1","4.9.10","4.9.11","4.9.12","4.9.13","4.9.14","4.9.15","4.9.2","4.9.3","4.9.4","4.9.5","4.9.6","4.9.7","4.9.8","4.9.9"],"fixed":["4.9.16"]},{"ecosystem":"Packagist","name":"contao/core-bundle","sources":[{"name":"OSV · GHSA-h58v-c6rf-g9f7","url":"https://osv.dev/vulnerability/GHSA-h58v-c6rf-g9f7"}],"ranges":[{"events":[{"introduced":"4.10.0"},{"fixed":"4.11.5"}],"type":"ECOSYSTEM"}],"versions":["4.10.0","4.10.1","4.10.2","4.10.3","4.10.4","4.10.5","4.10.6","4.10.7","4.11.0","4.11.0-RC1","4.11.0-RC2","4.11.1","4.11.2","4.11.3","4.11.4"],"fixed":["4.11.5"]},{"ecosystem":"Packagist","name":"contao/contao","sources":[{"name":"OSV · GHSA-h58v-c6rf-g9f7","url":"https://osv.dev/vulnerability/GHSA-h58v-c6rf-g9f7"}],"ranges":[{"events":[{"introduced":"4.5.0"},{"fixed":"4.9.16"}],"type":"ECOSYSTEM"}],"versions":["4.5.13","4.5.14","4.6.0","4.6.1","4.6.10","4.6.11","4.6.12","4.6.13","4.6.14","4.6.2","4.6.3","4.6.4","4.6.5","4.6.6","4.6.7","4.6.8","4.6.9","4.7.0","4.7.0-RC1","4.7.0-RC2","4.7.0-RC3","4.7.0-RC4","4.7.1","4.7.2","4.7.3","4.7.4","4.7.5","4.7.6","4.7.7","4.8.0","4.8.0-RC1","4.8.0-RC2","4.8.1","4.8.2","4.8.3","4.8.4","4.8.5","4.8.6","4.8.7","4.8.8","4.9.0","4.9.0-RC1","4.9.0-RC2","4.9.1","4.9.10","4.9.11","4.9.12","4.9.13","4.9.14","4.9.15","4.9.2","4.9.3","4.9.4","4.9.5","4.9.6","4.9.7","4.9.8","4.9.9"],"fixed":["4.9.16"]},{"ecosystem":"Packagist","name":"contao/contao","sources":[{"name":"OSV · GHSA-h58v-c6rf-g9f7","url":"https://osv.dev/vulnerability/GHSA-h58v-c6rf-g9f7"}],"ranges":[{"events":[{"introduced":"4.10.0"},{"fixed":"4.11.5"}],"type":"ECOSYSTEM"}],"versions":["4.10.0","4.10.1","4.10.2","4.10.3","4.10.4","4.10.5","4.10.6","4.10.7","4.11.0","4.11.0-RC1","4.11.0-RC2","4.11.1","4.11.2","4.11.3","4.11.4"],"fixed":["4.11.5"]}],"sourceAffected":[],"references":["https://github.com/contao/contao/security/advisories/GHSA-h58v-c6rf-g9f7","https://nvd.nist.gov/vuln/detail/CVE-2021-35210","https://contao.org/en/security-advisories/cross-site-scripting-in-the-system-log-2021.html","https://github.com/FriendsOfPHP/security-advisories/blob/master/contao/contao/CVE-2021-35210.yaml","https://github.com/FriendsOfPHP/security-advisories/blob/master/contao/core-bundle/CVE-2021-35210.yaml","https://github.com/contao/contao"],"sources":[{"name":"OSV","id":"GHSA-h58v-c6rf-g9f7","modified":"2026-09-10T03:49:06.413015318Z","url":"https://osv.dev/vulnerability/GHSA-h58v-c6rf-g9f7"}],"assessments":[{"source":"OSV","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","score":6.1}],"products":[],"remediation":[],"kev":{"status":"not-listed","checkedAt":"2026-10-28T20:20:32.181Z"},"coverage":[{"source":"NVD","status":"not-checked"},{"source":"GHSA","status":"not-checked"},{"source":"EUVD","status":"not-checked"},{"source":"EPSS","status":"not-checked"}],"evidence":[]}