CVE-2021-36854Network attack vector

Unauthorized changes via missing AJAX nonce checks

Published Sep 30, 2022 · Updated Apr 28, 2026

Cross-Site Request Forgery in Booking Ultra Pro Appointments Booking Calendar Plugin 1.1.4 and earlier allows remote attackers to alter site data via forged requests. The plugin's AJAX action handlers omit or incorrectly validate WordPress nonces, allowing crafted cross-site requests to execute administrative operations when a logged-in administrator is induced to click a link. Exploitation requires administrator interaction and can change booking settings, inject scripts, or expose staff information.

CVSS severity8.8
High
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-Site Request Forgery in Booking Ultra Pro Appointments Booking Calendar Plugin 1.1.4 and earlier allows remote attackers to alter site data via forged requests. The plugin's AJAX action handlers omit or incorrectly validate WordPress nonces, allowing crafted cross-site requests to execute administrative operations when a logged-in administrator is induced to click a link. Exploitation requires administrator interaction and can change booking settings, inject scripts, or expose staff information.

The record

CVE
CVE-2021-36854
Published
Sep 30, 2022
Updated
Apr 28, 2026
Vendor
Booking Ultra Pro
Product
Booking Ultra Pro Appointments Booking Calendar Plugin
Classifications
CWE-352
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 30, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 28, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=<= 1.1.4 <=1.1.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Booking Ultra Pro · Booking Ultra Pro Appointments Booking Calendar Pluginversion=<= 1.1.4 <=1.1.4

Published CVSS scores

8.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
5.4PatchstackCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-352Cross-Site Request Forgery (CSRF)

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

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Your stack

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