CVE-2021-24513: The Form Builder | Create Responsive Contact Forms WordPress plugin before 1.9.8.4 does not sanitise or escape

Q: How do I fix CVE-2021-24513?

form builder: upgrade to 1.9.8.4. Exact commands for each OS are on this page.

Q: Is CVE-2021-24513 being exploited?

CVE-2021-24513 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-24513 affect?

CVE-2021-24513 affects form builder. Severity is medium (CVSS 5.4). The Form Builder | Create Responsive Contact Forms WordPress plugin before 1.9.8.4 does not sanitise or escape its Form Title, allowing high privilege users such as admin to set Cross-Site Scripting payload in them, even when the unfiltered

Q: How urgent is CVE-2021-24513?

Priority 36/100. Public exploit reference

Routine

MEDIUM 5.4UPGRADE

CVE-2021-24513 is a medium-severity flaw (CVSS 5.4) affecting form builder. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The Form Builder | Create Responsive Contact Forms WordPress plugin before 1.9.8.4 does not sanitise or escape its Form Title, allowing high privilege users such as admin to set Cross-Site Scripting payload in them, even when the unfiltered_html capability is disallowed

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	5.4 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	Required
EPSS exploit chance	0.6% (top 50%)
CISA exploited list	No
Weakness	CWE-79
Published	2021-09-06
Last modified	2026-06-17

Publisher (CNA): WPScan · Vendor: web-settler

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-09-06 11:15 UTCPublished CVE record published
2026-06-17 03:40 UTCUpdated Record last modified

web-settler form builder UPGRADE

Affected: < 1.9.8.4

Fixed in: 1.9.8.4

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy form-builder || rpm -q form-builder || form-builder --version

2. UPGRADE to 1.9.8.4 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade form-builder

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade form-builder

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-24513?

form builder: upgrade to 1.9.8.4. Exact commands for each OS are on this page.

Is CVE-2021-24513 being exploited?

CVE-2021-24513 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-24513 affect?

CVE-2021-24513 affects form builder. Severity is medium (CVSS 5.4). The Form Builder | Create Responsive Contact Forms WordPress plugin before 1.9.8.4 does not sanitise or escape its Form Title, allowing high privilege users such as admin to set Cross-Site Scripting payload in them, even when the unfiltered

How urgent is CVE-2021-24513?

Priority 36/100. Public exploit reference

Software pages

WordPress vulnerabilities

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References

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