CVE-2021-41464Public exploitNetwork attack vector

Reflected XSS via unsanitized rel parameter

Published Oct 1, 2021 · Updated Aug 4, 2024

Reflected XSS in concrete/elements/collection_add.php in concrete5-legacy 5.6.4.0 and earlier allows remote attackers to run script. The element writes the rel query parameter into the edit-collection popup without sufficient sanitization, allowing crafted markup to enter the response. Exploitation requires a victim to follow a crafted link, after which the injected code runs in that victim's browser context and can act with the victim's session.

CVSS severity6.1
Medium
EPSS probability0.84%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected XSS in concrete/elements/collection_add.php in concrete5-legacy 5.6.4.0 and earlier allows remote attackers to run script. The element writes the rel query parameter into the edit-collection popup without sufficient sanitization, allowing crafted markup to enter the response. Exploitation requires a victim to follow a crafted link, after which the injected code runs in that victim's browser context and can act with the victim's session.

The record

CVE
CVE-2021-41464
Published
Oct 1, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 1, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.1NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
4.3NIST National Vulnerability DatabaseAV:N/AC:M/Au:N/C:N/I:P/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 11, 2026Sep 17, 2026
Latest reporting daySep 17, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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