CVE-2021-21797: Gonitro Nitro Pro

High severity, CVSS 7.8. EPSS: 15% chance of exploitation in the next 30 days.

An exploitable double-free vulnerability exists in the JavaScript implementation of Nitro Pro PDF. A specially crafted document can cause a reference to a timeout object to be stored in two different places. When closed, the document will result in the reference being released twice. This can lead to code execution under the context of the application. An attacker can convince a user to open a document to trigger this vulnerability.

Affected products

• Gonitro Nitro Pro: version 13.31.0.605 only; version 13.33.2.645 only

Published 2021-10-18. Last modified 2026-06-17.