CVE-2021-21870
CVSS v3
8.8
HIGH
EPSS Score
1.9 %
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 10.1.4.37651. A specially crafted PDF document can trigger the reuse of previously free memory, which can lead to arbitrary code execution. An attacker needs to trick the user into opening a malicious file or site to trigger this vulnerability if the browser plugin extension is enabled.
Technical details
- Published
- 2021-08-05
Frequently asked questions
What is CVE-2021-21870?
A use-after-free vulnerability exists in the JavaScript engine of Foxit Software’s PDF Reader, version 10.1.4.37651. A specially crafted PDF document can trigger the reuse of previously free memory, which can lead to arbitrary code execution. An attacker needs to trick the user into opening a malicious file or site to trigger this vulnerability if the browser plugin extension is enabled.
Is CVE-2021-21870 actively exploited?
Active exploitation of CVE-2021-21870 has not been confirmed. Its EPSS score was 1.9% on 2026-09-25, the estimated probability of exploitation in the next 30 days.
What is the CVSS score for CVE-2021-21870?
CVE-2021-21870 has a CVSS v3 base score of 8.8 (HIGH severity).
Is CVE-2021-21870 affecting your environment?
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