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CVE-2021-24884: 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 exploi

critical Affects formidable-form-builder (WordPress plugin). Feed 2026.10.29.1, updated 2026-10-28; published ; advisory modified .

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 exploi

Package
formidable-form-builder (WordPress plugin) WordPress
Affected versions
<4.09.05
Fixed in
4.09.05
Severity
critical  CVSS 9.6
Exploitation
not on CISA KEV · EPSS 3% (87.8th percentile)
Published
2021-10-25
Source
nvd

References

CWE-352CWE-79
NVD recordformidable-form-builder (WordPress plugin) advisories

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# PHP projects (recommended)
composer require --dev phpwarden/phpwarden
# then
vendor/bin/phpwarden wordpress /var/www/html

# or, without Composer
pipx install phpwarden   &&   phpwarden wordpress /var/www/html

Or keep it checked automatically with the GitHub Action or a nightly cron; see WordPress docs.

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