CVE-2026-25435

High

Published: 25 March 2026

Published

25 March 2026

Modified

24 April 2026

KEV Added

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Patch

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CVSS Score v3.1 7.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L

EPSS Score 0.0004 14.4th percentile

Risk Priority 14 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-25435 is a high-severity Cross-site Scripting (CWE-79) vulnerability. Its CVSS base score is 7.1 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 14.4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-15 (Information Output Filtering).

Deeper analysis

CVE-2026-25435 is an Improper Neutralization of Input During Web Page Generation vulnerability, classified as Stored Cross-site Scripting (XSS) under CWE-79, in the wpdevart Booking Calendar, Appointment Booking System WordPress plugin (booking-calendar). This issue affects all versions from n/a through 3.2.36, as published on 2026-03-25.

The vulnerability carries a CVSS v3.1 base score of 7.1 (AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L), indicating network accessibility, low attack complexity, no required privileges, and user interaction needed for exploitation, with changed scope and low impacts on confidentiality, integrity, and availability. Unauthenticated attackers can inject and store malicious scripts via the plugin, which then execute in victims' browsers when they access affected pages, such as booking calendars.

Patchstack's database entry details the Stored XSS vulnerability in the Booking Calendar, Appointment Booking System plugin, specifically referencing version 3.2.35; practitioners should consult this advisory (https://patchstack.com/database/Wordpress/Plugin/booking-calendar/vulnerability/wordpress-booking-calendar-appointment-booking-system-plugin-3-2-35-cross-site-scripting-xss-vulnerability?_s_id=cve) for mitigation guidance, including any available patches or workarounds.

EU & UK References

🇪🇺 ENISA EUVD: EUVD-2026-15726

Vulnerability details

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in wpdevart Booking calendar, Appointment Booking System booking-calendar allows Stored XSS.This issue affects Booking calendar, Appointment Booking System: from n/a through <= 3.2.36.

CWE(s): CWE-79

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

T1059.007 JavaScript Execution

Adversaries may abuse various implementations of JavaScript for execution.

attack.mitre.org →

Why these techniques?

Stored XSS in public-facing WordPress plugin directly enables exploitation of the web application (T1190) and arbitrary JavaScript execution in victim browsers (T1059.007).

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1