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PatchSiren cyber security CVE debrief

CVE-2026-1856 creavi CVE debrief

The Appointment Booking Calendar plugin for WordPress is vulnerable to Stored Cross-Site Scripting via custom booking field labels in all versions up to, and including, 1.4.4. This vulnerability is due to insufficient input sanitization and output escaping, allowing authenticated attackers with Author-level access and above to inject arbitrary web scripts. These scripts will execute whenever a user accesses an injected page, potentially impacting users and requiring review of compensating controls.

Vendor
creavi
Product
Creavi Appointment Booking Calendar
CVSS
MEDIUM 6.4
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-19
Original CVE updated
2026-06-22
Advisory published
2026-06-19
Advisory updated
2026-06-22

Who should care

Authenticated attackers with Author-level access and above could inject arbitrary web scripts, impacting users accessing injected pages. Operators of WordPress deployments using the Appointment Booking Calendar plugin should review their exposure and consider security measures to protect against potential attacks.

Technical summary

The Appointment Booking Calendar plugin for WordPress is vulnerable to Stored Cross-Site Scripting via custom booking field labels in all versions up to, and including, 1.4.4. This is due to insufficient input sanitization and output escaping, allowing authenticated attackers with Author-level access and above to inject arbitrary web scripts. These scripts will execute whenever a user accesses an injected page, potentially impacting users and requiring review of compensating controls and security measures.

Defensive priority

Medium priority due to CVSS score of 6.4 and potential impact on users accessing injected pages, requiring review of security measures and compensating controls.

Recommended defensive actions

  • Update to a patched version of the Appointment Booking Calendar plugin
  • Restrict access to the plugin's settings and functionality to trusted users only
  • Monitor for suspicious activity and injected scripts on affected pages
  • Consider implementing additional security measures such as Web Application Firewall (WAF) rules to detect and prevent similar 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

Evidence notes

CVE-2026-1856 was published on 2026-06-19T06:17:01.807Z and last modified on 2026-06-22T19:16:50.793Z. The NVD entry is currently Deferred. Evidence is limited to CVE and NVD details. Defenders should verify affected product deployments and review official advisories for scope and severity.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-1856 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-1856

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-1856 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-1856

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental 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.