CVE-2021-24516: The PlanSo Forms WordPress plugin through 2.6.3 does not escape the title of its Form before outputting it in

Q: How do I fix CVE-2021-24516?

planso forms: upgrade to newer than 2.6.3. Exact commands for each OS are on this page.

Q: Is CVE-2021-24516 being exploited?

CVE-2021-24516 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-2021-24516 affect?

CVE-2021-24516 affects planso forms. Severity is medium (CVSS 4.8). The PlanSo Forms WordPress plugin through 2.6.3 does not escape the title of its Form before outputting it in attributes, allowing high privilege users such as admin to set XSS payload in it, even when the unfiltered_html is disallowed, lea

Q: How urgent is CVE-2021-24516?

Priority 34/100. Public exploit reference

Routine

MEDIUM 4.8UPGRADE

CVE-2021-24516 is a medium-severity flaw (CVSS 4.8) affecting planso forms. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The PlanSo Forms WordPress plugin through 2.6.3 does not escape the title of its Form before outputting it in attributes, allowing high privilege users such as admin to set XSS payload in it, even when the unfiltered_html is disallowed, leading to an Authenticated Stored Cross-Site Scripting issue.

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	4.8 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	High
User interaction	Required
EPSS exploit chance	0.6% (top 49%)
CISA exploited list	No
Weakness	CWE-79
Published	2021-10-18
Last modified	2026-06-17

Publisher (CNA): WPScan · Vendor: planso

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

Am I affected?

Timeline

2021-10-18 14:15 UTCPublished CVE record published
2026-06-17 03:40 UTCUpdated Record last modified

planso planso forms UPGRADE

Affected: <= 2.6.3

Fixed in: newer than 2.6.3

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy planso-forms || rpm -q planso-forms || planso-forms --version

2. UPGRADE to newer than 2.6.3 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade planso-forms

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade planso-forms

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-2021-24516?

planso forms: upgrade to newer than 2.6.3. Exact commands for each OS are on this page.

Is CVE-2021-24516 being exploited?

CVE-2021-24516 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-2021-24516 affect?

CVE-2021-24516 affects planso forms. Severity is medium (CVSS 4.8). The PlanSo Forms WordPress plugin through 2.6.3 does not escape the title of its Form before outputting it in attributes, allowing high privilege users such as admin to set XSS payload in it, even when the unfiltered_html is disallowed, lea

How urgent is CVE-2021-24516?

Priority 34/100. Public exploit reference

Software pages

WordPress vulnerabilities

References

← Back to latest CVEs