{"cve":"CVE-2021-42078","nvd":{"published":"2021-11-08T05:15:07.553","modified":"2026-06-17T04:09:16.437","status":"Modified","description":"PHP Event Calendar through 2021-11-04 allows persistent cross-site scripting (XSS), as demonstrated by the /server/ajax/events_manager.php title parameter. This can be exploited by an adversary in multiple ways, e.g., to perform actions on the page in the context of other users, or to deface the site.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","score":6.1},"cwes":["CWE-79"],"references":["http://seclists.org/fulldisclosure/2021/Nov/24","https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2021-049.txt","http://seclists.org/fulldisclosure/2021/Nov/24","https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2021-049.txt"],"products":["php_event_calendar_project:php_event_calendar"],"source":"nvd","synced_at":"2026-10-19T21:24:39.218183596+00:00"},"epss":{"cve":"CVE-2021-42078","score":0.00893,"percentile":0.5946,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}