CVE-2021-42245: FlatCore-CMS 2.0.9 has a cross-site scripting (XSS) vulnerability in pages.edit.php through meta tags and cont

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MEDIUM 6.1DOWNGRADE

CVE-2021-42245 is a medium-severity flaw (CVSS 6.1) affecting flatcore-cms. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

FlatCore-CMS 2.0.9 has a cross-site scripting (XSS) vulnerability in pages.edit.php through meta tags and content sections.

Why this priority

Public exploit reference

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	6.1 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.7% (top 46%)
CISA exploited list	No
Weakness	CWE-79
Published	2022-06-06
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: flatcore

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

Am I affected?

Timeline

2022-06-06 12:15 UTCPublished CVE record published
2026-06-17 04:09 UTCUpdated Record last modified

flatcore flatcore-cms DOWNGRADE

Affected: 2.0.9

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.0.9

1. Check installed version

apt-cache policy flatcore-cms || rpm -q flatcore-cms || flatcore-cms --version

2. No fixed release: DOWNGRADE to a release before 2.0.9 (Debian / Ubuntu)

apt-cache madison flatcore-cms sudo apt install flatcore-cms=<VERSION_BEFORE_2.0.9> sudo apt-mark hold flatcore-cms

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list flatcore-cms sudo dnf downgrade flatcore-cms-<VERSION_BEFORE_2.0.9> sudo dnf versionlock add flatcore-cms

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

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-2021-42245?

flatcore-cms: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-42245 being exploited?

CVE-2021-42245 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-2021-42245 affect?

CVE-2021-42245 affects flatcore-cms. Severity is medium (CVSS 6.1). FlatCore-CMS 2.0.9 has a cross-site scripting (XSS) vulnerability in pages.edit.php through meta tags and content sections.

How urgent is CVE-2021-42245?

Priority 40/100. Public exploit reference

Software pages

PHP vulnerabilities

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References

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