CVE-2021-4252: A vulnerability, which was classified as problematic, has been found in WP-Ban

Q: How do I fix CVE-2021-4252?

wp-ban: upgrade to 2021-11-24. Exact commands for each OS are on this page.

Q: Is CVE-2021-4252 being exploited?

CVE-2021-4252 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-2021-4252 affect?

CVE-2021-4252 affects wp-ban. Severity is low (CVSS 3.5). A vulnerability, which was classified as problematic, has been found in WP-Ban. This issue affects the function toggle_checkbox of the file ban-options.php. The manipulation of the argument $_SERVER["HTTP_USER_AGENT"] leads to cross site sc

Q: How urgent is CVE-2021-4252?

Priority 23/100. No elevated risk signals yet.

Routine

LOW 3.5UPGRADE

CVE-2021-4252 is a low-severity flaw (CVSS 3.5) affecting wp-ban. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A vulnerability, which was classified as problematic, has been found in WP-Ban. This issue affects the function toggle_checkbox of the file ban-options.php. The manipulation of the argument $_SERVER["HTTP_USER_AGENT"] leads to cross site scripting. The attack may be initiated remotely. The name of the patch is 13e0b1e922f3aaa3f8fcb1dd6d50200dd693fd76. It is recommended to apply a patch to fix this issue. The identifier VDB-216209 was assigned to

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	3.5 (Low)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	Required
EPSS exploit chance	0.5% (top 57%)
CISA exploited list	No
Weakness	CWE-707
Published	2022-12-18
Last modified	2026-06-17

Publisher (CNA): VulDB · Vendor: wp-ban project

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

Am I affected?

Timeline

2022-12-18 22:15 UTCPublished CVE record published
2026-06-17 04:19 UTCUpdated Record last modified

wp-ban project wp-ban UPGRADE

Affected: < 2021-11-24

Fixed in: 2021-11-24

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy wp-ban || rpm -q wp-ban || wp-ban --version

2. UPGRADE to 2021-11-24 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade wp-ban

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade wp-ban

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-2021-4252?

wp-ban: upgrade to 2021-11-24. Exact commands for each OS are on this page.

Is CVE-2021-4252 being exploited?

CVE-2021-4252 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-2021-4252 affect?

CVE-2021-4252 affects wp-ban. Severity is low (CVSS 3.5). A vulnerability, which was classified as problematic, has been found in WP-Ban. This issue affects the function toggle_checkbox of the file ban-options.php. The manipulation of the argument $_SERVER["HTTP_USER_AGENT"] leads to cross site sc

How urgent is CVE-2021-4252?

Priority 23/100. No elevated risk signals yet.

Software pages

PHP vulnerabilities

Related CVEs

CVE-2022-4631 LOW 3.5 MITIGATE A vulnerability, which was classified as problematic, was found in WP-Ban
CVE-2022-4260 MEDIUM 4.8 UPGRADE The WP-Ban WordPress plugin before 1.69.1 does not sanitise and escape some of its settings, which could allow

References

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