CVE-2021-21831

Pdf Reader vulnerability

CVSS

8.8

EPSS

4.5%

EPSS pct

91th

Exploited

No known

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 vendor

Foxit

Affected product

Pdf Reader

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Weakness type (CWE)

CWE-416 — Use After Free

Published

2021-08-05

Risk analysis

Based on its CVSS vector, this vulnerability is exploitable over the network, low attack complexity, requiring no privileges, user interaction. Successful exploitation leads to high impact to confidentiality, high impact to integrity, high impact to availability.

Its EPSS score of 4.5% reflects a lower probability of exploitation activity in the wild over the next 30 days, placing it above 91% of all scored CVEs.

Check your external exposure to CVE-2021-21831

Confirm whether Foxit Pdf Reader is running on any internet-facing host or subdomain.
Match discovered service fingerprints against the version affected by CVE-2021-21831.
Prioritise remediation if the asset is public, business-critical, or near authentication/payment flows.

How ThreatPort helps with CVE-2021-21831

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