Medium

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

IdentifiersCVE-2026-5940CWE-416· Use After Free

CVE-2026-5940 is a use-after-free vulnerability in Foxit PDF Reader involving the handling of Annotation objects. According to the provided advisory context, calling a function that triggers a UI refresh after comments are removed via a script can result in access to an invalidated object. The flaw is caused by insufficient validation that the object still exists before subsequent operations are performed on it. This memory-safety issue can lead to a crash and, under attacker-controlled conditions, can be leveraged for arbitrary code execution within the Foxit PDF Reader process.

For your environment

Are you exposed to this one?

Mallory correlates every CVE against your assets, your vendors, and active adversary campaigns. Know which vulnerabilities matter for you, not just which ones are loud.

Start free trial

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 can allow a remote attacker to execute arbitrary code in the context of the current Foxit PDF Reader process. The vulnerability may also cause application crashes due to dereferencing an invalidated object. Because the issue is reachable through malicious content opened or rendered by the application, exploitation can result in compromise of confidentiality, integrity, and availability for data accessible to the user context of the process.

Mitigation

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

Until patches are fully deployed, reduce exposure by avoiding opening untrusted PDF files or visiting untrusted pages that may invoke Foxit PDF Reader content handling. Limit use of scripting-capable PDF content where operationally feasible, and apply standard hardening controls such as least-privilege execution, attachment filtering, web-content filtering, and isolating PDF handling in protected environments.

Remediation

Patch, then assume compromise.

Apply the vendor-provided Foxit PDF Reader update referenced by Foxit and the ZDI advisory. The provided content states that Foxit has issued an update to correct the vulnerability. Upgrade affected installations to the fixed version identified in Foxit's security bulletins.

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.

Start free trial

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-2026-5940

NVD

nvd.nist.gov/vuln/detail/CVE-2026-5940

MITRE CWE · CWE-416

Use After Free

Vendor Advisory

foxit.com/support/security-bulletins.html