CVE-2026-66490: Joomla Extension - balbooa.com - Stored cross-site scripting via a comment avatar in Gridbox < 2.20.2

Q: How do I fix CVE-2026-66490?

gridbox: upgrade to 2.20.2. Exact commands for each OS are on this page.

Q: Is CVE-2026-66490 being exploited?

CVE-2026-66490 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-2026-66490 affect?

CVE-2026-66490 affects gridbox. Severity is medium (CVSS 6.1). Joomla Extension - balbooa.com - Stored cross-site scripting via a comment avatar in Gridbox < 2.20.2

Q: How urgent is CVE-2026-66490?

Priority 26/100. No elevated risk signals yet.

Routine

MEDIUM 6.1UPGRADE

CVE-2026-66490 is a medium-severity flaw (CVSS 6.1) affecting gridbox. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Joomla Extension - balbooa.com - Stored cross-site scripting via a comment avatar in Gridbox < 2.20.2

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	0.3% (top 82%)
CISA exploited list	No
Weakness	CWE-79
Published	2026-07-29
Last modified	2026-10-23

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

Last updated 2026-10-23 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-29 14:16 UTCPublished CVE record published
2026-10-23 23:10 UTCUpdated Record last modified

balbooa gridbox UPGRADE

Affected: < 2.20.2

Fixed in: 2.20.2

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 2.20.2 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade gridbox

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-2026-66490?

gridbox: upgrade to 2.20.2. Exact commands for each OS are on this page.

Is CVE-2026-66490 being exploited?

CVE-2026-66490 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-2026-66490 affect?

CVE-2026-66490 affects gridbox. Severity is medium (CVSS 6.1). Joomla Extension - balbooa.com - Stored cross-site scripting via a comment avatar in Gridbox < 2.20.2

How urgent is CVE-2026-66490?

Priority 26/100. No elevated risk signals yet.

Software pages

Joomla vulnerabilities

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References

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