CVE-2021-24789: The Flat Preloader WordPress plugin before 1.5.5 does not escape some of its settings when outputting them in

Q: How do I fix CVE-2021-24789?

flat preloader: upgrade to 1.5.5. Exact commands for each OS are on this page.

Q: Is CVE-2021-24789 being exploited?

CVE-2021-24789 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-2021-24789 affect?

CVE-2021-24789 affects flat preloader. Severity is medium (CVSS 4.8). The Flat Preloader WordPress plugin before 1.5.5 does not escape some of its settings when outputting them in attribute in the frontend, which could allow high privilege users to perform Cross-Site Scripting attacks even when the unfiltered

Q: How urgent is CVE-2021-24789?

Priority 34/100. Public exploit reference

Routine

MEDIUM 4.8UPGRADE

CVE-2021-24789 is a medium-severity flaw (CVSS 4.8) affecting flat preloader. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The Flat Preloader WordPress plugin before 1.5.5 does not escape some of its settings when outputting them in attribute in the frontend, which could allow high privilege users to perform Cross-Site Scripting attacks even when the unfiltered_html is disallowed

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	2021-11-01
Last modified	2026-06-17

Publisher (CNA): WPScan · Vendor: flat preloader project

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

Am I affected?

Timeline

2021-11-01 09:15 UTCPublished CVE record published
2026-06-17 03:40 UTCUpdated Record last modified

flat preloader project flat preloader UPGRADE

Affected: < 1.5.5

Fixed in: 1.5.5

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy flat-preloader || rpm -q flat-preloader || flat-preloader --version

2. UPGRADE to 1.5.5 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade flat-preloader

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade flat-preloader

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-2021-24789?

flat preloader: upgrade to 1.5.5. Exact commands for each OS are on this page.

Is CVE-2021-24789 being exploited?

CVE-2021-24789 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-2021-24789 affect?

CVE-2021-24789 affects flat preloader. Severity is medium (CVSS 4.8). The Flat Preloader WordPress plugin before 1.5.5 does not escape some of its settings when outputting them in attribute in the frontend, which could allow high privilege users to perform Cross-Site Scripting attacks even when the unfiltered

How urgent is CVE-2021-24789?

Priority 34/100. Public exploit reference

Software pages

WordPress vulnerabilities

Related CVEs

CVE-2021-24685 MEDIUM 5.4 UPGRADE The Flat Preloader WordPress plugin before 1.5.4 does not enforce nonce checks when saving its settings, as we

References

← Back to latest CVEs