CVE-2026-83546 CoolClock CVE debrief

Who should care

Defenders responsible for WordPress installations with the CoolClock plugin, and users with contributor-level access and above, should assess exposure and prioritize verification and updates.

Why it matters

The CoolClock WordPress plugin vulnerability allows users with contributor-level access and above to inject arbitrary web scripts, requiring defenders to assess exposure and prioritize verification and updates.

• Defenders must verify and update the CoolClock WordPress plugin to version 4.3.8 or later to prevent potential XSS attacks
• Users with contributor-level access and above may be able to inject arbitrary web scripts, requiring monitoring and access controls
• The vulnerability may allow for potential code execution, requiring defenders to assess exposure and prioritize remediation

Technical summary

The CoolClock WordPress plugin before 4.3.8 does not properly escape a skin setting before outputting it within an HTML attribute, allowing users with contributor-level access and above to inject arbitrary web scripts that execute when the content is viewed. This vulnerability requires defenders to verify and update the plugin to version 4.3.8 or later, and assess exposure for users with contributor-level access and above. The vulnerability allows for potential code execution, requiring defenders to prioritize verification and updates.

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 suspicious activity related to the CoolClock plugin
• 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 evidence is available on exploitation or impact. Defenders should verify the CoolClock WordPress plugin version and assess exposure for users with contributor-level access and above. The vulnerability detail pages do not provide explicit evidence of exploitation, but they do offer source-provided CVE metadata and source-specific vulnerability assessments.

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.