{"schemaVersion":3,"id":"CVE-2021-24884","aliases":[],"status":"published","duplicateOf":null,"title":null,"description":"The Formidable Form Builder WordPress plugin before 4.09.05 allows to inject certain HTML Tags like <audio>,<video>,<img>,<a> and<button>.This could allow an unauthenticated, remote attacker to exploit a HTML-injection byinjecting a malicous link. The HTML-injection may trick authenticated users to follow the link. If the Link gets clicked, Javascript code can be executed. The vulnerability is due to insufficient sanitization of the \"data-frmverify\" tag for links in the web-based entry inspection page of affected systems. A successful exploitation incomibantion with CSRF could allow the attacker to perform arbitrary actions on an affected system with the privileges of the user. These actions include stealing the users account by changing their password or allowing attackers to submit their own code through an authenticated user resulting in Remote Code Execution. If an authenticated user who is able to edit Wordpress PHP Code in any kind, clicks the malicious link, PHP code can be edited.","dates":{"published":"2021-10-25T13:20:59.000Z","modified":"2024-08-03T19:49:14.206Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":9.6,"severity":"critical","version":"3.1","versionLabel":"v3.1","source":"NVD","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H","computed":false,"selection":"backend-summary"},"metrics":[{"version":"3.1","versionLabel":"v3.1","source":"NVD","score":9.6,"severity":"critical","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H","exploitability":null,"impact":null,"computed":false},{"version":"2.0","versionLabel":"v2.0","source":"NVD","score":6.8,"severity":"medium","vector":"AV:N/AC:M/Au:N/C:P/I:P/A:P","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"wordfence","score":9.6,"severity":"critical","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H","exploitability":null,"impact":null,"computed":false}]},"epss":{"probability":0.03134,"percentile":0.87715,"severity":"low","asOf":"2026-10-20T00:00:00.000Z","change":{"pp":0,"baselineDate":"2026-09-20T00:00:00.000Z","baselineScore":0.03134},"history":[{"date":"2026-09-14T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-09-15T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-09-16T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-09-17T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-09-18T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-09-19T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.03134,"percentile":0.87715}],"last30":[{"date":"2026-09-20T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.03134,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.03134,"percentile":0.87715}]},"kev":{"state":"not-listed","entries":[],"listedCount":0,"totalCatalogs":3,"catalogs":[{"source":"cisa","label":"CISA","listed":false,"entry":null},{"source":"enisa","label":"ENISA","listed":false,"entry":null},{"source":"circl","label":"CIRCL","listed":false,"entry":null}]},"ransomware":{"state":"none-recorded","sources":[]},"exploits":[{"id":"GITHUB_S1LKYS_XSS-IN-FORMIDABLE-4.09.04","name":"Xss In Formidable 4.09.04","source":"github","url":"https://github.com/S1lkys/XSS-in-Formidable-4.09.04/blob/main/XSS-in-Formidable-4.09.04.pdf","maturity":"poc","reliabilityScore":0.3,"verified":false,"type":null,"platforms":[],"requiresAuth":null,"exploitdb":null,"metasploit":null},{"id":"REF_1BFF475BEEC9B396","name":"Exploit Reference (wpscan.com)","source":"reference","url":"https://wpscan.com/vulnerability/b57dacdd-43c2-48f8-ac1e-eb8306b22533","maturity":"unknown","reliabilityScore":0.2,"verified":false,"type":null,"platforms":[],"requiresAuth":null,"exploitdb":null,"metasploit":null}],"exploitCount":2,"weaknesses":[{"id":"CWE-352","name":"Cross-Site Request Forgery (CSRF)","description":"The web application does not, or cannot, sufficiently verify whether a request was intentionally provided by the user who sent the request, which could have originated from an unauthorized actor.","type":"weakness","status":"Stable","abstraction":"Compound","likelihoodOfExploit":"Medium","url":"https://cwe.mitre.org/data/definitions/352.html"},{"id":"CWE-79","name":"Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')","description":"The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.","type":"weakness","status":"Stable","abstraction":"Base","likelihoodOfExploit":"High","url":"https://cwe.mitre.org/data/definitions/79.html"}],"affected":[{"vendor":"strategy11","product":"formidable_form_builder","name":"formidable form builder","label":"formidable_form_builder","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"< 4.09.05","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 4.09.05","eol":null,"hubHref":"/vendor/strategy11/formidable_form_builder"},{"vendor":"unknown","product":"formidable form builder – contact form, survey & quiz forms plugin for wordpress","name":"Formidable Form Builder – Contact Form, Survey & Quiz Forms Plugin for WordPress","label":"formidable form builder – contact form, survey & quiz forms plugin for wordpress","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"≥ 4.09.05, < 4.09.05","noFixRecorded":false,"fixedIn":null}],"versionsText":"≥ 4.09.05, < 4.09.05","eol":null,"hubHref":"/vendor/unknown/formidable_form_builder_-_contact_form_survey__quiz_forms_plugin_for_wordpress"},{"vendor":"wordpress","product":"formidable","name":"Formidable Forms – WordPress Form Builder for Contact Forms, Calculators, Quizzes & More","label":"formidable","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"< 4.09.05","noFixRecorded":false,"fixedIn":"4.09.05"}],"versionsText":"< 4.09.05","eol":null,"hubHref":null}],"affectedCount":3,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://wpscan.com/vulnerability/b57dacdd-43c2-48f8-ac1e-eb8306b22533","label":"wpscan.com/vulnerability/b57dacdd-43c2-48f8-ac1e-eb8306b22533","hostname":"wpscan.com","tags":["X Refsource MISC","Exploit","Third Party Advisory"]},{"url":"https://github.com/Strategy11/formidable-forms/pull/335/files","label":"github.com/Strategy11/formidable-forms/pull/335/files","hostname":"github.com","tags":["X Refsource MISC","Patch","Third Party Advisory"]},{"url":"https://github.com/S1lkys/XSS-in-Formidable-4.09.04/blob/main/XSS-in-Formidable-4.09.04.pdf","label":"github.com/S1lkys/XSS-in-Formidable-4.09.04/blob/main/XSS-in-Formidable-4.09.04.pdf","hostname":"github.com","tags":["X Refsource MISC","Exploit","Third Party Advisory"]},{"url":"https://www.wordfence.com/threat-intel/vulnerabilities/id/ef5028a0-6a5a-40ad-92df-ffc988cad389","label":"www.wordfence.com/threat-intel/vulnerabilities/id/ef5028a0-6a5a-40ad-92df-ffc988cad389","hostname":"www.wordfence.com","tags":["Vendor Advisory"]}],"lineage":{"upstream":[],"downstream":[],"duplicates":[],"related":[]},"timeline":[{"kind":"published","date":"2021-10-25T13:20:59.000Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2024-08-03T19:49:14.206Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":70,"level":"high","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-21T05:07:55.250Z","stale":false,"partial":false}}