CVE-2026-23899: An improper access check allows unauthorized access to webservice endpoints.

Routine

HIGH 8.8UPGRADE

CVE-2026-23899 is a high-severity flaw (CVSS 8.8) affecting joomla\!. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An improper access check allows unauthorized access to webservice endpoints.

Why this priority

High severity

A fixed release or distro patch exists.

Risk facts

CVSS score	8.8 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.4% (top 66%)
CISA exploited list	No
Weakness	CWE-284
Published	2026-04-01
Last modified	2026-10-26

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

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-01 10:16 UTCPublished CVE record published
2026-10-26 21:10 UTCUpdated Record last modified

joomla joomla\! UPGRADE

Affected: >= 3.0.0 and < 5.4.4 · >= 6.0.0 and < 6.0.4

Fixed in: 5.4.4, 6.0.4

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 5.4.4 (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-2026-23899?

joomla\!: upgrade to 5.4.4, 6.0.4. Exact commands for each OS are on this page.

Is CVE-2026-23899 being exploited?

CVE-2026-23899 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-2026-23899 affect?

CVE-2026-23899 affects joomla\!. Severity is high (CVSS 8.8). An improper access check allows unauthorized access to webservice endpoints.

How urgent is CVE-2026-23899?

Priority 39/100. High severity

Software pages

Joomla vulnerabilities

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References

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