{"cve":"CVE-2021-39357","nvd":{"published":"2021-10-21T20:15:08.260","modified":"2026-06-17T04:03:37.057","status":"Modified","description":"The Leaky Paywall WordPress plugin is vulnerable to Stored Cross-Site Scripting due to insufficient input validation and sanitization via the ~/class.php file which allowed attackers with administrative user access to inject arbitrary web scripts, in versions up to and including 4.16.5. This affects multi-site installations where unfiltered_html is disabled for administrators, and sites where unfiltered_html is disabled.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N","score":4.8},"cwes":["CWE-79"],"references":["https://github.com/BigTiger2020/word-press/blob/main/Leaky%20Paywall.md","https://plugins.trac.wordpress.org/changeset/2615195/leaky-paywall/trunk/class.php","https://wordfence.com/vulnerability-advisories/#CVE-2021-39357","https://github.com/BigTiger2020/word-press/blob/main/Leaky%20Paywall.md","https://plugins.trac.wordpress.org/changeset/2615195/leaky-paywall/trunk/class.php"],"products":["zeen101:leaky_paywall"],"source":"nvd","synced_at":"2026-10-19T21:24:39.218183596+00:00"},"epss":{"cve":"CVE-2021-39357","score":0.00915,"percentile":0.60157,"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."]}