CVE-2025-55420: A Reflected Cross Site Scripting (XSS) vulnerability was found in /index.php in FoxCMS v1.2.6

This month

HIGH 8.8DOWNGRADE

CVE-2025-55420 is a high-severity flaw (CVSS 8.8) affecting foxcms. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A Reflected Cross Site Scripting (XSS) vulnerability was found in /index.php in FoxCMS v1.2.6. When a crafted script is sent via a GET request, it is reflected unsanitized into the HTML response. This permits execution of arbitrary JavaScript code when a logged-in user submits the malicious input.

Why this priority

High severity
Public exploit reference

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

Risk facts

CVSS score	8.8 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.5% (top 58%)
CISA exploited list	No
Weakness	CWE-79
Published	2025-08-21
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: foxcms

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

Am I affected?

Timeline

2025-08-21 16:15 UTCPublished CVE record published
2026-06-17 09:41 UTCUpdated Record last modified

foxcms foxcms DOWNGRADE

Affected: 1.2.6

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.2.6

1. Check installed version

apt-cache policy foxcms || rpm -q foxcms || foxcms --version

2. No fixed release: DOWNGRADE to a release before 1.2.6 (Debian / Ubuntu)

apt-cache madison foxcms sudo apt install foxcms=<VERSION_BEFORE_1.2.6> sudo apt-mark hold foxcms

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

dnf --showduplicates list foxcms sudo dnf downgrade foxcms-<VERSION_BEFORE_1.2.6> sudo dnf versionlock add foxcms

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-2025-55420?

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

Is CVE-2025-55420 being exploited?

CVE-2025-55420 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-2025-55420 affect?

CVE-2025-55420 affects foxcms. Severity is high (CVSS 8.8). A Reflected Cross Site Scripting (XSS) vulnerability was found in /index.php in FoxCMS v1.2.6. When a crafted script is sent via a GET request, it is reflected unsanitized into the HTML response. This permits execution of arbitrary JavaScri

How urgent is CVE-2025-55420?

Priority 46/100. High severity; Public exploit reference

Software pages

PHP vulnerabilities

Related CVEs

CVE-2025-10251 MEDIUM 6.3 UPGRADE A vulnerability was detected in FoxCMS up to 1.24
CVE-2025-12920 LOW 2.4 UPGRADE A flaw has been found in qianfox FoxCMS up to 1.2.16
CVE-2025-11306 MEDIUM 4.3 UPGRADE A vulnerability was found in qianfox FoxCMS up to 1.2
CVE-2025-55422 HIGH 8.8 DOWNGRADE In FoxCMS 1.2.6, there is a reflected Cross Site Scripting (XSS) vulnerability in /index.php/plus.
CVE-2025-55409 HIGH 8.8 DOWNGRADE FoxCMS 1.2.6, there is a Cross Site Scripting vulnerability in /index.php/article

References

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