The telepathy Hello Bar Popup Builder up to version 1.5.1 contains a DOM-based Cross-site Scripting vulnerability caused by improper neutralization of input during web page generation. This allows an attacker to inject and execute malicious scripts in the context of the affected web page. The vulnerability is identified as CVE-2026-39666 and was published on 2026-04-08. No CVSS score or official remediation is currently available, and no known exploits have been reported. The product is not a cloud service, so remediation depends on vendor patching or user updates.

Successful exploitation of this vulnerability could allow an attacker to execute arbitrary scripts in the context of users visiting a web page using the vulnerable Hello Bar Popup Builder. This may lead to theft of user credentials, session hijacking, or other client-side attacks. However, no known exploits are currently reported, and the exact impact depends on the context in which the Hello Bar Popup Builder is used.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is released, users should consider disabling or removing the vulnerable Hello Bar Popup Builder component or applying any available workarounds recommended by the vendor. Monitor vendor channels for updates regarding patches or mitigations.