CVE-2026-59516 is a reflected cross-site scripting vulnerability in ICS Calendar by Room 34 Creative Services, LLC. The vulnerability arises from improper neutralization of input during web page generation, allowing attackers to inject malicious scripts that execute in the context of the victim's browser. This affects ICS Calendar versions up to and including 12.1.1. The CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L) indicates network attack vector, low complexity, no privileges required, user interaction required, scope changed, and low impact on confidentiality, integrity, and availability.

Successful exploitation can lead to execution of arbitrary scripts in the context of the victim's browser, potentially resulting in information disclosure, session hijacking, or other user-targeted impacts. The vulnerability affects confidentiality, integrity, and availability to a low degree. The scope is changed, meaning the vulnerability affects components beyond the initially vulnerable component.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or workaround has been documented at this time. Until a patch is available, users should exercise caution with untrusted input and consider implementing web application firewall rules or input validation as temporary mitigations.