CVE-2026-83545 CoolClock CVE debrief

Who should care

Defenders responsible for WordPress installations with the CoolClock plugin, particularly those with users having contributor-level access and above, should assess exposure and prioritize updating the plugin.

Why it matters

The CoolClock WordPress plugin vulnerability allows users with contributor-level access and above to inject arbitrary JavaScript, potentially leading to code execution, data theft, or manipulation. Defenders should prioritize verifying and updating the plugin, assessing exposure, and monitoring for potential attacks.

• Potential JavaScript injection attacks
• Arbitrary code execution on affected systems
• Possible data theft or manipulation
• Required verification of plugin version and user access levels

Technical summary

The CoolClock WordPress plugin before 4.3.8 does not properly escape a custom skin setting before outputting it inside an inline script, allowing users with contributor-level access and above to inject arbitrary JavaScript that executes when the content is viewed. This vulnerability could lead to potential JavaScript injection attacks, arbitrary code execution on affected systems, and possible data theft or manipulation. The vulnerability is related to improper input validation and output encoding, which allows an attacker to inject malicious JavaScript code.

Defensive priority

Defenders should prioritize verifying and updating the CoolClock WordPress plugin to version 4.3.8 or later, and assess exposure for users with contributor-level access and above.

Recommended defensive actions

• Verify and update the CoolClock WordPress plugin to version 4.3.8 or later
• Assess exposure for users with contributor-level access and above
• Monitor for potential JavaScript injection attacks
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and NVD vulnerability detail page provide information on the vulnerability, but limited details are available on exploitation or impact. The CoolClock WordPress plugin vulnerability allows users with contributor-level access and above to inject arbitrary JavaScript. Defenders should verify plugin version and user access levels, assess exposure, and monitor for potential attacks. Limited source details are available; explicit evidence is required for defensive actions.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.