CVE-2021-21831: Foxit PDF Reader

High severity, CVSS 8.8. EPSS: 6.1% chance of exploitation in the next 30 days.

A use-after-free vulnerability exists in the JavaScript engine of Foxit Software’s PDF Reader, version 10.1.3.37598. A specially crafted PDF document can trigger the reuse of previously freed memory, which can lead to arbitrary code execution. An attacker needs to trick the user to open the malicious file to trigger this vulnerability. Exploitation is also possible if a user visits a specially crafted, malicious site if the browser plugin extension is enabled.

Affected products

• Foxit PDF Reader: version 10.1.3.37598 only

Published 2021-08-05. Last modified 2026-06-17.