CVE-2021-24670Network attack vector

Stored script execution via unescaped shortcode attributes

Published Sep 27, 2021 · Updated Aug 3, 2024

Stored XSS in Rolf Allard van Hagen CoolClock before 4.3.5 allows remote authenticated users to execute script via shortcode attributes. The shortcode renderer places certain contributor-controlled attributes into generated page output without context-appropriate escaping. Contributor access is sufficient to store the payload, and script runs in the affected site's origin when another user views the content.

CVSS severity5.4
Medium
EPSS probability0.62%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Stored XSS in Rolf Allard van Hagen CoolClock before 4.3.5 allows remote authenticated users to execute script via shortcode attributes. The shortcode renderer places certain contributor-controlled attributes into generated page output without context-appropriate escaping. Contributor access is sufficient to store the payload, and script runs in the affected site's origin when another user views the content.

The record

CVE
CVE-2021-24670
Published
Sep 27, 2021
Updated
Aug 3, 2024
Vendor
Rolf Allard van Hagen
Product
CoolClock
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 27, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.3.5 <4.3.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Rolf Allard van Hagen · CoolClockversion=4.3.5 <4.3.5

Published CVSS scores

5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
3.5NIST NVDAV:N/AC:M/Au:S/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007JavaScript/JScript

Public exploit references

No public exploit references are available in this record.

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

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo