CVE-2009-1940: Cross-site scripting (XSS) vulnerability in the administrator panel in the com_users core component for Joomla

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MEDIUM 4.3DOWNGRADE

CVE-2009-1940 is a medium-severity flaw (CVSS 4.3) affecting joomla. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Cross-site scripting (XSS) vulnerability in the administrator panel in the com_users core component for Joomla! 1.5.x through 1.5.10 allows remote attackers to inject arbitrary web script or HTML via unspecified vectors.

Why this priority

Public exploit reference

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

Risk facts

CVSS score	4.3 (Medium)
EPSS exploit chance	2.0% (top 19%)
CISA exploited list	No
Weakness	CWE-79
Published	2009-06-05
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: joomla

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

Am I affected?

Timeline

2009-06-05 18:30 UTCPublished CVE record published
2026-06-16 23:08 UTCUpdated Record last modified

joomla joomla DOWNGRADE

Affected: 1.5 · 1.5.1 · 1.5.2 · 1.5.3 · 1.5.4 · 1.5.5 · 1.5.6 · 1.5.7

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.5

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 1.5 (Debian / Ubuntu)

apt-cache madison joomla sudo apt install joomla=<VERSION_BEFORE_1.5> sudo apt-mark hold joomla

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

dnf --showduplicates list joomla sudo dnf downgrade joomla-<VERSION_BEFORE_1.5> sudo dnf versionlock add joomla

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-2009-1940?

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

Is CVE-2009-1940 being exploited?

CVE-2009-1940 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-2009-1940 affect?

CVE-2009-1940 affects joomla. Severity is medium (CVSS 4.3). Cross-site scripting (XSS) vulnerability in the administrator panel in the com_users core component for Joomla! 1.5.x through 1.5.10 allows remote attackers to inject arbitrary web script or HTML via unspecified vectors.

How urgent is CVE-2009-1940?

Priority 40/100. Public exploit reference

Software pages

Joomla vulnerabilities

Related CVEs

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CVE-2008-6299 LOW 3.5 UPGRADE Multiple cross-site scripting (XSS) vulnerabilities in Joomla! 1.5.7 and earlier allow remote authenticated us

References

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