CVE-2011-5255: Multiple cross-site scripting (XSS) vulnerabilities in admin/login in X3 CMS 0.4.3.1 and earlier allow remote

Q: How do I fix CVE-2011-5255?

x3 cms: upgrade to newer than 0.4.3.1. Exact commands for each OS are on this page.

Q: Is CVE-2011-5255 being exploited?

CVE-2011-5255 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-2011-5255 affect?

CVE-2011-5255 affects x3 cms. Severity is medium (CVSS 4.3). Multiple cross-site scripting (XSS) vulnerabilities in admin/login in X3 CMS 0.4.3.1 and earlier allow remote attackers to inject arbitrary web script or HTML via the (1) PATH_INFO, (2) username, or (3) password parameter.

Q: How urgent is CVE-2011-5255?

Priority 39/100. Public exploit reference

Routine

MEDIUM 4.3UPGRADE

CVE-2011-5255 is a medium-severity flaw (CVSS 4.3) affecting x3 cms. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Multiple cross-site scripting (XSS) vulnerabilities in admin/login in X3 CMS 0.4.3.1 and earlier allow remote attackers to inject arbitrary web script or HTML via the (1) PATH_INFO, (2) username, or (3) password parameter.

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	4.3 (Medium)
EPSS exploit chance	1.7% (top 23%)
CISA exploited list	No
Weakness	CWE-79
Published	2013-01-31
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: x3cms

Last updated 2026-06-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2013-01-31 05:44 UTCPublished CVE record published
2026-06-16 23:36 UTCUpdated Record last modified

x3cms x3 cms UPGRADE

Affected: <= 0.4.3.1 · 0.4 rc2 · 0.4.0.3 · 0.4.1 · 0.4.2 · 0.4.2.1

Fixed in: newer than 0.4.3.1

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy x3-cms || rpm -q x3-cms || x3-cms --version

2. UPGRADE to newer than 0.4.3.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade x3-cms

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade x3-cms

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-2011-5255?

x3 cms: upgrade to newer than 0.4.3.1. Exact commands for each OS are on this page.

Is CVE-2011-5255 being exploited?

CVE-2011-5255 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-2011-5255 affect?

CVE-2011-5255 affects x3 cms. Severity is medium (CVSS 4.3). Multiple cross-site scripting (XSS) vulnerabilities in admin/login in X3 CMS 0.4.3.1 and earlier allow remote attackers to inject arbitrary web script or HTML via the (1) PATH_INFO, (2) username, or (3) password parameter.

How urgent is CVE-2011-5255?

Priority 39/100. Public exploit reference

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CVE-2014-8772 LOW 3.5 DOWNGRADE Cross-site scripting (XSS) vulnerability in the search_controller in X3 CMS 0.5.1 and 0.5.1.1 allows remote au
CVE-2014-8771 MEDIUM 6.8 DOWNGRADE Multiple cross-site request forgery (CSRF) vulnerabilities in the admin area in X3 CMS 0.5.1 and 0.5.1.1 allow

References

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