CVE-2024-11855Network attack vector

Stored XSS via unescaped shortcode height

Published Dec 14, 2024 · Updated Apr 8, 2026

Stored XSS in Koalendar – Easy Appointment Scheduling & Booking Plugin 1.0.2 and earlier allows remote authenticated users to inject scripts via height. The [koalendar] shortcode places the height attribute into generated iframe markup without adequate input sanitization or output escaping. Contributor-level access is required to store the payload, which executes in a visitor's browser whenever the injected page is viewed.

CVSS severity6.4
Medium
EPSS probability0.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Koalendar – Easy Appointment Scheduling & Booking Plugin 1.0.2 and earlier allows remote authenticated users to inject scripts via height. The [koalendar] shortcode places the height attribute into generated iframe markup without adequate input sanitization or output escaping. Contributor-level access is required to store the payload, which executes in a visitor's browser whenever the injected page is viewed.

The record

CVE
CVE-2024-11855
Published
Dec 14, 2024
Updated
Apr 8, 2026
Vendor
Koalendar
Product
Koalendar – Easy Appointment Scheduling & Booking Plugin
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 14, 2024CVE publishedPublication date reported by the CVE source.
  2. Apr 8, 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=0 <=1.0.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Koalendar · Koalendar – Easy Appointment Scheduling & Booking Pluginversion=0 <=1.0.2

Published CVSS scores

6.4WordfenceCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007Command and Scripting Interpreter: JavaScript

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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