CVE-2021-39599: Multiple Cross Site Scripting (XSS) vulnerabilities exists in CXUUCMS 3.1 in the search and c parameters in (1

Routine

MEDIUM 6.1DOWNGRADE

CVE-2021-39599 is a medium-severity flaw (CVSS 6.1) affecting cxuucms. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Multiple Cross Site Scripting (XSS) vulnerabilities exists in CXUUCMS 3.1 in the search and c parameters in (1) public/search.php and in the (2) c parameter in admin.php.

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	0.6% (top 49%)
CISA exploited list	No
Weakness	CWE-79
Published	2021-08-23
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: cxuu

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

Am I affected?

Timeline

2021-08-23 23:15 UTCPublished CVE record published
2026-06-17 04:03 UTCUpdated Record last modified

cxuu cxuucms DOWNGRADE

Affected: 3.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.1

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 3.1 (Debian / Ubuntu)

apt-cache madison cxuucms sudo apt install cxuucms=<VERSION_BEFORE_3.1> sudo apt-mark hold cxuucms

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

dnf --showduplicates list cxuucms sudo dnf downgrade cxuucms-<VERSION_BEFORE_3.1> sudo dnf versionlock add cxuucms

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-2021-39599?

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

Is CVE-2021-39599 being exploited?

CVE-2021-39599 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-2021-39599 affect?

CVE-2021-39599 affects cxuucms. Severity is medium (CVSS 6.1). Multiple Cross Site Scripting (XSS) vulnerabilities exists in CXUUCMS 3.1 in the search and c parameters in (1) public/search.php and in the (2) c parameter in admin.php.

How urgent is CVE-2021-39599?

Priority 39/100. Public exploit reference

Software pages

PHP vulnerabilities

Related CVEs

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CVE-2021-3264 HIGH 7.2 DOWNGRADE SQL Injection vulnerability in cxuucms 3.1 ivia the pid parameter in public/admin.php.
CVE-2020-35347 MEDIUM 6.5 DOWNGRADE CXUUCMS V3 3.1 has a CSRF vulnerability that can add an administrator account via admin.php?c=adminuser&a=add.
CVE-2020-35346 MEDIUM 4.8 DOWNGRADE CXUUCMS V3 3.1 is affected by a reflected XSS vulnerability that allows remote attackers to inject arbitrary w
CVE-2020-29250 MEDIUM 6.1 DOWNGRADE CXUUCMS V3 allows XSS via the first and third input fields to /public/admin.php.

References

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