CVE-2026-21623: Lack of input filterung leads to a persistent XSS vulnerability in the forum post handling of the Easy Discuss

Routine

MEDIUM 5.4UPGRADE

CVE-2026-21623 is a medium-severity flaw (CVSS 5.4) affecting easydiscuss. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Lack of input filterung leads to a persistent XSS vulnerability in the forum post handling of the Easy Discuss component for Joomla.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	5.4 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	Required
EPSS exploit chance	0.2% (top 91%)
CISA exploited list	No
Weakness	CWE-79
Published	2026-01-16
Last modified	2026-06-17

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

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-01-16 15:15 UTCPublished CVE record published
2026-06-17 10:18 UTCUpdated Record last modified

stackideas easydiscuss UPGRADE

Affected: >= 1.0.0 and <= 5.0.15

Fixed in: newer than 5.0.15

Safe to downgrade to: a release before 1.0.0

1. Check installed version

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

2. UPGRADE to newer than 5.0.15 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade easydiscuss

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 1.0.0 (Debian / Ubuntu)

apt-cache madison easydiscuss sudo apt install easydiscuss=<VERSION_BEFORE_1.0.0> sudo apt-mark hold easydiscuss

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

dnf --showduplicates list easydiscuss sudo dnf downgrade easydiscuss-<VERSION_BEFORE_1.0.0> sudo dnf versionlock add easydiscuss

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-2026-21623?

easydiscuss: upgrade to newer than 5.0.15. Exact commands for each OS are on this page.

Is CVE-2026-21623 being exploited?

CVE-2026-21623 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-2026-21623 affect?

CVE-2026-21623 affects easydiscuss. Severity is medium (CVSS 5.4). Lack of input filterung leads to a persistent XSS vulnerability in the forum post handling of the Easy Discuss component for Joomla.

How urgent is CVE-2026-21623?

Priority 21/100. No elevated risk signals yet.

Software pages

Joomla vulnerabilities

Related CVEs

CVE-2026-21626 HIGH 7.5 UPGRADE Access control settings for forum post custom fields are not applied to the JSON output type, leading to an AC
CVE-2026-21625 HIGH 8.8 UPGRADE User provided uploads to the Easy Discuss component for Joomla aren't properly validated
CVE-2026-21624 MEDIUM 5.4 UPGRADE Lack of input filterung leads to a persistent XSS vulnerability in the user avatar text handling of the Easy D

References

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