CVE-2026-3779

High

Published: 01 April 2026

Published

01 April 2026

Modified

01 April 2026

KEV Added

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Patch

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CVSS Score 7.8 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS Score 0.0002 4.3th percentile

Risk Priority 16 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-3779 is a high-severity Use After Free (CWE-416) vulnerability in Foxit (inferred from references). Its CVSS base score is 7.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Client Execution (T1203); ranked at the 4.3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified are NIST 800-53 SC-39 (Process Isolation) and SI-16 (Memory Protection).

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploitation for Client Execution (T1203) and 1 other technique. What defenders deploy: see the NIST 800-53 controls recommended below.

Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

SI-2 Flaw Remediation good match

prevent

Requires timely identification, reporting, and correction of the use-after-free flaw in Foxit software, eliminating the vulnerability exploited by crafted documents.

SI-16 Memory Protection good match

prevent

Implements memory protection methods such as ASLR and DEP that prevent exploitation of use-after-free vulnerabilities to achieve arbitrary code execution.

SC-39 Process Isolation good match

prevent

Provides process isolation for the Foxit application, containing potential code execution from stale object references within a separate execution domain.

MITRE ATT&CK Enterprise TechniquesAI

T1203 Exploitation for Client Execution Execution

Adversaries may exploit software vulnerabilities in client applications to execute code.

attack.mitre.org →

T1204.002 Malicious File Execution

An adversary may rely upon a user opening a malicious file in order to gain execution.

attack.mitre.org →

Why these techniques?

Use-after-free in Foxit PDF viewer enables arbitrary code execution via crafted document opened by user, directly mapping to client-side exploitation and malicious file user execution.

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

NVD Description

The application's list box calculate array logic keeps stale references to page or form objects after they are deleted or re-created, which allows crafted documents to trigger a use-after-free when the calculation runs and can potentially lead to arbitrary code…

execution.

Deeper analysisAI

CVE-2026-3779 is a use-after-free vulnerability (CWE-416) affecting Foxit software, published on 2026-04-01. The issue resides in the application's list box calculate array logic, which retains stale references to page or form objects after they are deleted or re-created. Crafted documents can exploit this flaw when the calculation runs, potentially leading to arbitrary code execution. The vulnerability has a CVSS v3.1 base score of 7.8 (AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H).

An attacker with local access can exploit this vulnerability with low complexity and no privileges required, but it demands user interaction. Typically, the attacker would trick a user into opening a malicious document within the affected Foxit application, triggering the use-after-free during list box calculations and enabling high-impact confidentiality, integrity, and availability violations through arbitrary code execution.

Mitigation details are available in the vendor's advisories at https://www.foxit.com/support/security-bulletins.html and the Talos Intelligence report at https://www.talosintelligence.com/vulnerability_reports/TALOS-2026-2365. Security practitioners should consult these resources for patch information, workarounds, and affected versions.