CVE-2021-41464: Cross-site scripting (XSS) vulnerability in concrete/elements/collection_add.php in concrete5-legacy 5.6.4.0 a

Q: How do I fix CVE-2021-41464?

concrete5-legacy: upgrade to newer than 5.6.4.0. Exact commands for each OS are on this page.

Q: Is CVE-2021-41464 being exploited?

CVE-2021-41464 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-2021-41464 affect?

CVE-2021-41464 affects concrete5-legacy. Severity is medium (CVSS 6.1). Cross-site scripting (XSS) vulnerability in concrete/elements/collection_add.php in concrete5-legacy 5.6.4.0 and below allows remote attackers to inject arbitrary web script or HTML via the rel parameter.

Q: How urgent is CVE-2021-41464?

Priority 41/100. Public exploit reference

This month

MEDIUM 6.1UPGRADE

CVE-2021-41464 is a medium-severity flaw (CVSS 6.1) affecting concrete5-legacy. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Cross-site scripting (XSS) vulnerability in concrete/elements/collection_add.php in concrete5-legacy 5.6.4.0 and below allows remote attackers to inject arbitrary web script or HTML via the rel parameter.

Why this priority

Public exploit reference

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	0.8% (top 42%)
CISA exploited list	No
Weakness	CWE-79
Published	2021-10-01
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: concrete5-legacy project

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

Am I affected?

Timeline

2021-10-01 16:15 UTCPublished CVE record published
2026-06-17 04:08 UTCUpdated Record last modified

concrete5-legacy project concrete5-legacy UPGRADE

Affected: <= 5.6.4.0

Fixed in: newer than 5.6.4.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy concrete5-legacy || rpm -q concrete5-legacy || concrete5-legacy --version

2. UPGRADE to newer than 5.6.4.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade concrete5-legacy

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade concrete5-legacy

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-2021-41464?

concrete5-legacy: upgrade to newer than 5.6.4.0. Exact commands for each OS are on this page.

Is CVE-2021-41464 being exploited?

CVE-2021-41464 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-2021-41464 affect?

CVE-2021-41464 affects concrete5-legacy. Severity is medium (CVSS 6.1). Cross-site scripting (XSS) vulnerability in concrete/elements/collection_add.php in concrete5-legacy 5.6.4.0 and below allows remote attackers to inject arbitrary web script or HTML via the rel parameter.

How urgent is CVE-2021-41464?

Priority 41/100. Public exploit reference

Software pages

PHP vulnerabilities

Related CVEs

CVE-2021-41465 MEDIUM 6.1 UPGRADE Cross-site scripting (XSS) vulnerability in concrete/elements/collection_theme.php in concrete5-legacy 5.6.4.0
CVE-2021-41463 MEDIUM 6.1 UPGRADE Cross-site scripting (XSS) vulnerability in toos/permissions/dialogs/access/entity/types/group_combination.php
CVE-2021-41462 MEDIUM 6.1 UPGRADE Cross-site scripting (XSS) vulnerability in concrete/elements/collection_add.php in concrete5-legacy 5.6.4.0 a
CVE-2021-41461 MEDIUM 6.1 UPGRADE Cross-site scripting (XSS) vulnerability in concrete/elements/collection_add.php in concrete5-legacy 5.6.4.0 a

References

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