High

Foxit PDF Reader AcroForm Annotation Use-After-Free Remote Code Execution

IdentifiersCVE-2026-5943CWE-416· Use After Free

CVE-2026-5943 is a remote code execution vulnerability in Foxit PDF Reader involving the handling of AcroForm Annotation objects. The flaw is a use-after-free condition caused by improper maintenance of object reference validity and insufficient validation that an object still exists before operations are performed on it. According to the provided context, document structural anomalies can desynchronize page element relationships from internal index state; when script-driven document modifications occur, Foxit may later access an invalid pointer during page information queries, resulting in a crash. In an exploit scenario, a specially crafted PDF file or malicious page can trigger the stale object access and potentially redirect execution flow, leading to arbitrary code execution in the context of the current process.

For your environment

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows a remote attacker to execute arbitrary code in the security context of the user running Foxit PDF Reader. The vulnerability can also cause application instability or a crash due to invalid pointer dereference. Because the issue is rated with high impact to confidentiality, integrity, and availability in the supplied CVSS vector, exploitation may enable full compromise of data accessible to the process, modification of user data, and disruption of service on the affected host.

Mitigation

If you can’t patch tonight, do this now.

Until the vendor patch is fully deployed, reduce exposure by preventing Foxit PDF Reader from opening untrusted PDF files and by avoiding visits to untrusted or attacker-controlled pages that may deliver malicious PDF content. Apply least-privilege for end users, use application control or sandboxing where available, and consider disabling or restricting active content/script execution in PDF workflows if operationally feasible. Email and web filtering for malicious PDF delivery can further reduce exploit opportunities.

Remediation

Patch, then assume compromise.

Foxit issued an update to correct this vulnerability, and the vendor published remediation information in its security bulletins. The appropriate remediation is to upgrade Foxit PDF Reader to the vendor-fixed version referenced in Foxit's April 2026 security update/advisory for CVE-2026-5943 and ensure the patched build is deployed across affected systems.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

Foxit SoftwarePdf Editorapplication

Foxit SoftwarePdf Readerapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

5 sources tracked across advisories and community write-ups. News coverage will land here when it surfaces.

5 SOURCESView more in app

No news coverage yet. Advisories and community discussion only.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.

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Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity4

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES

MITRE CVE

cve.org · CVE-2026-5943

NVD

nvd.nist.gov/vuln/detail/CVE-2026-5943

MITRE CWE · CWE-416

Use After Free

Vendor Advisory

foxit.com/support/security-bulletins.html