CVE-2026-39601 WPdevelop CVE debrief

Who should care

Defenders responsible for WordPress installations with the Booking Calendar plugin should assess exposure and potential impact. This includes evaluating the plugin's usage, privileges, and the sensitivity of the data it handles. Prioritization should be given to environments where the plugin is used for critical scheduling or appointment management functions, as the vulnerability could lead to service disruptions or

Why it matters

Defenders should prioritize verifying exposure and assessing potential impact of the race condition vulnerability in the Booking Calendar plugin for WordPress.

• Verification of exposure is required to determine if the Booking Calendar plugin is installed and vulnerable.
• Assessment of potential impact is necessary to evaluate the plugin's usage and privileges.

Technical summary

A race condition vulnerability in the Booking Calendar plugin for WordPress, affecting versions from n/a through 11.8.4, allows attackers to leverage this issue. This vulnerability could lead to unintended behavior in the scheduling and appointment management features of the plugin. The plugin's failure to properly synchronize access to shared resources creates a window for attackers to exploit, potentially leading to data inconsistencies or service disruptions.

Defensive priority

Defenders should prioritize verifying exposure and assessing potential impact.

Recommended defensive actions

• Verify exposure by checking if the Booking Calendar plugin is installed and if the version is prior to 11.8.4.
• Assess potential impact by evaluating the plugin's usage and privileges.
• Consider updating the plugin to a version that addresses the vulnerability.

Evidence notes

The CVE record and NVD detail page provide information on the vulnerability, but further verification is needed to determine affected versions and potential impact.

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.