{"cve":{"cve_id":"CVE-2021-21359","is_kev":false,"kev_date_added":null,"kev_vendor_project":null,"kev_product":null,"kev_vulnerability_name":null,"kev_short_description":null,"kev_required_action":null,"kev_due_date":null,"kev_known_ransomware":null,"kev_notes":null,"kev_cwes":null,"epss_score":0.01731,"epss_percentile":0.74658,"epss_as_of":"2026-06-23","description":"TYPO3 is an open source PHP based web content management system. In TYPO3 before versions 9.5.25, 10.4.14, 11.1.1 requesting invalid or non-existing resources via HTTP triggers the page error handler which again could retrieve content to be shown as error message from another page. This leads to a scenario in which the application is calling itself recursively - amplifying the impact of the initial attack until the limits of the web server are exceeded. This is fixed in versions 9.5.25, 10.4.14, 11.1.1.","published_at":"2021-03-23T01:55:19Z","last_modified_at":null,"cvss_v3_score":5.9,"cvss_v3_vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","cvss_v3_severity":"MEDIUM","cvss_v4_score":null,"cvss_v4_vector":null,"cvss_v4_severity":null,"ssvc_decision":null,"ssvc_exploitation":null,"ssvc_automatable":null,"ssvc_technical_impact":null,"cwes":["CWE-674","CWE-405"],"nvd_references":["https://packagist.org/packages/typo3/cms-core","https://github.com/TYPO3/TYPO3.CMS/security/advisories/GHSA-4p9g-qgx9-397p","https://typo3.org/security/advisory/typo3-core-sa-2021-005"],"vuln_status":null,"trending_score":null,"is_trending":false,"has_trended":false,"trended_number_one":false,"trending_peak_score":null,"trending_peak_rank":null,"started_trending_at":null,"trended_number_one_at":null,"summary_generated":null,"summary_generated_at":null,"summary_model":null,"created_at":"2026-06-24T00:09:39.878444Z","updated_at":"2026-06-28T23:14:57.707777Z"},"effective_severity":"MEDIUM","badges":[],"impact_analysis":[],"cvss_v3_decoded":{"version":"3.1","metrics":[{"metric":"AV","name":"Attack Vector","value":"N","value_label":"Network"},{"metric":"AC","name":"Attack Complexity","value":"H","value_label":"High"},{"metric":"PR","name":"Privileges Required","value":"N","value_label":"None"},{"metric":"UI","name":"User Interaction","value":"N","value_label":"None"},{"metric":"S","name":"Scope","value":"U","value_label":"Unchanged"},{"metric":"C","name":"Confidentiality","value":"N","value_label":"None"},{"metric":"I","name":"Integrity","value":"N","value_label":"None"},{"metric":"A","name":"Availability","value":"H","value_label":"High"}]},"cvss_v4_decoded":{"version":null,"metrics":[]},"affected":[{"vendor_slug":"typo3","vendor_name":"TYPO3","product_slug":"typo3.cms","product_name":"TYPO3.CMS","version_start":">= 9.0.0, <= 9.5.24","version_start_inclusive":true,"version_end":">= 9.0.0, <= 9.5.24","version_end_inclusive":true,"cpe23_uri":"cve5:typo3:typo3.cms:>= 9.0.0, <= 9.5.24:>= 9.0.0, <= 9.5.24"},{"vendor_slug":"typo3","vendor_name":"TYPO3","product_slug":"typo3.cms","product_name":"TYPO3.CMS","version_start":">= 10.0.0, <= 10.4.13","version_start_inclusive":true,"version_end":">= 10.0.0, <= 10.4.13","version_end_inclusive":true,"cpe23_uri":"cve5:typo3:typo3.cms:>= 10.0.0, <= 10.4.13:>= 10.0.0, <= 10.4.13"},{"vendor_slug":"typo3","vendor_name":"TYPO3","product_slug":"typo3.cms","product_name":"TYPO3.CMS","version_start":">= 11.0.0, <= 11.1.0","version_start_inclusive":true,"version_end":">= 11.0.0, <= 11.1.0","version_end_inclusive":true,"cpe23_uri":"cve5:typo3:typo3.cms:>= 11.0.0, <= 11.1.0:>= 11.0.0, <= 11.1.0"}],"exploit_refs":[],"news":[],"references":[{"url":"https://packagist.org/packages/typo3/cms-core","source_type":"MISC","tags":[]},{"url":"https://github.com/TYPO3/TYPO3.CMS/security/advisories/GHSA-4p9g-qgx9-397p","source_type":"VENDOR_ADVISORY","tags":["advisory"]},{"url":"https://typo3.org/security/advisory/typo3-core-sa-2021-005","source_type":"MISC","tags":[]}],"timeline":[{"type":"published","at":"2021-03-23T01:55:19Z","label":"CVE published","source":null},{"type":"cvss_changed","at":"2026-06-28T17:05:11.212102Z","label":"CVSS score revised","source":"cvelistv5"},{"type":"cvss_changed","at":"2026-06-28T17:05:11.212102Z","label":"CVSS score revised","source":"cvelistv5"},{"type":"cvss_changed","at":"2026-06-28T17:05:11.212102Z","label":"CVSS score revised","source":"cvelistv5"}]}