CVE-2025-63589: A reflected XSS vulnerability exists in CMSimple_XH 1.8's index.php router when attacker-controlled path segme

Routine

HIGH 7.1DOWNGRADE

CVE-2025-63589 is a high-severity flaw (CVSS 7.1) affecting cmsimple xh. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A reflected XSS vulnerability exists in CMSimple_XH 1.8's index.php router when attacker-controlled path segments are not sanitized or encoded before being inserted into the generated HTML (navigation links, breadcrumbs, search form action, footer links). An attacker-controlled string placed in the URL path is reflected into multiple HTML elements, allowing execution of arbitrary JavaScript in victims' browsers visiting a crafted URL.

Why this priority

High severity
Public exploit reference

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

Risk facts

CVSS score	7.1 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.4% (top 71%)
CISA exploited list	No
Weakness	CWE-79
Published	2025-11-06
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: cmsimple-xh

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

Am I affected?

Timeline

2025-11-06 17:15 UTCPublished CVE record published
2026-06-17 09:53 UTCUpdated Record last modified

cmsimple-xh cmsimple xh DOWNGRADE

Affected: 1.8.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.8.0

1. Check installed version

apt-cache policy cmsimple-xh || rpm -q cmsimple-xh || cmsimple-xh --version

2. No fixed release: DOWNGRADE to a release before 1.8.0 (Debian / Ubuntu)

apt-cache madison cmsimple-xh sudo apt install cmsimple-xh=<VERSION_BEFORE_1.8.0> sudo apt-mark hold cmsimple-xh

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

dnf --showduplicates list cmsimple-xh sudo dnf downgrade cmsimple-xh-<VERSION_BEFORE_1.8.0> sudo dnf versionlock add cmsimple-xh

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-2025-63589?

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

Is CVE-2025-63589 being exploited?

CVE-2025-63589 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-2025-63589 affect?

CVE-2025-63589 affects cmsimple xh. Severity is high (CVSS 7.1). A reflected XSS vulnerability exists in CMSimple_XH 1.8's index.php router when attacker-controlled path segments are not sanitized or encoded before being inserted into the generated HTML (navigation links, breadcrumbs, search form action,

How urgent is CVE-2025-63589?

Priority 37/100. High severity; Public exploit reference

Software pages

PHP vulnerabilities

Related CVEs

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CVE-2024-34452 MEDIUM 6.1 DOWNGRADE CMSimple_XH 1.7.6 allows XSS by uploading a crafted SVG document.
CVE-2021-47736 HIGH 7.2 DOWNGRADE CMSimple_XH 1.7.4 contains an authenticated remote code execution vulnerability in the content editing functio

References

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