CVE-2021-21831
CVSS v3
8.8
HIGH
EPSS Score
6.2 %
exploit probability, as of 2026-09-25
CISA KEV
No
known exploited
Exploitation
—
SSVC status
Description
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.
Technical details
- Published
- 2021-08-05
Frequently asked questions
What is CVE-2021-21831?
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.
Is CVE-2021-21831 actively exploited?
Active exploitation of CVE-2021-21831 has not been confirmed. Its EPSS score was 6.2% on 2026-09-25, the estimated probability of exploitation in the next 30 days.
What is the CVSS score for CVE-2021-21831?
CVE-2021-21831 has a CVSS v3 base score of 8.8 (HIGH severity).
Is CVE-2021-21831 affecting your environment?
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