CVE-2026-48903: Inadequate content filtering within the checkAttribute methods leads to XSS vulnerabilities in various compone

Routine

MEDIUM 6.1UPGRADE

CVE-2026-48903 is a medium-severity flaw (CVSS 6.1) affecting joomla\!. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Inadequate content filtering within the checkAttribute methods leads to XSS vulnerabilities in various components.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	6.1 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.1% (top 96%)
CISA exploited list	No
Weakness	CWE-79
Published	2026-05-26
Last modified	2026-07-24

Publisher (CNA): Joomla! Project · Vendor: joomla

Last updated 2026-07-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-26 17:16 UTCPublished CVE record published
2026-07-24 11:10 UTCUpdated Record last modified

joomla joomla\! UPGRADE

Affected: >= 3.0.0 and < 5.4.6 · >= 6.0.0 and < 6.1.1

Fixed in: 5.4.6, 6.1.1

Safe to downgrade to: a release before 3.0.0

1. Check installed version

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

2. UPGRADE to 5.4.6 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade joomla

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade joomla

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 3.0.0 (Debian / Ubuntu)

apt-cache madison joomla sudo apt install joomla=<VERSION_BEFORE_3.0.0> sudo apt-mark hold joomla

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list joomla sudo dnf downgrade joomla-<VERSION_BEFORE_3.0.0> 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-2026-48903?

joomla\!: upgrade to 5.4.6, 6.1.1. Exact commands for each OS are on this page.

Is CVE-2026-48903 being exploited?

CVE-2026-48903 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-2026-48903 affect?

CVE-2026-48903 affects joomla\!. Severity is medium (CVSS 6.1). Inadequate content filtering within the checkAttribute methods leads to XSS vulnerabilities in various components.

How urgent is CVE-2026-48903?

Priority 22/100. No elevated risk signals yet.

Software pages

Joomla vulnerabilities

Related CVEs

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CVE-2026-21629 HIGH 7.3 UPGRADE The ajax component was excluded from the default logged-in-user check in the administrative area
CVE-2026-23898 HIGH 7.2 UPGRADE Lack of input validation leads to an arbitrary file deletion vulnerability in the autoupdate server mechanism.
CVE-2026-21631 MEDIUM 5.4 UPGRADE Lack of output escaping leads to a XSS vector in the multilingual associations component.

References

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