CVE-2026-57252: Foxit PDF Reader/Editor Use-After-Free Denial of Service Vulnerability

Technical summary

CVE-2026-57252 is a use-after-free vulnerability (CWE-416) affecting Foxit PDF Editor and Reader on Windows systems. When JavaScript within a PDF executes page deletion and attachment annotation removal operations in sequence, the attachment panel maintains references to freed memory objects. Subsequent panel operations attempt to dereference these invalid pointers, triggering an unhandled exception and application crash. The vulnerability stems from insufficient synchronization between the JavaScript execution context and the UI component lifecycle. The CVSS 3.1 score of 7.8 (HIGH) reflects local attack vector, low complexity, no privileges required, and user interaction as the sole mitigation—though the impact spans confidentiality, integrity, and availability due to memory corruption potential.

Business impact

Reliable application crashes degrade user trust and productivity, particularly for organizations reliant on PDF workflows for document review and processing. While the immediate impact is denial of service rather than data exfiltration, the underlying use-after-free condition creates a potential stepping stone for memory disclosure or code execution in advanced attacks. For enterprises using Foxit products in security-sensitive roles (e.g., legal discovery, financial document handling), malicious PDF delivery via email or file-sharing platforms poses credible risk. The low barrier to exploitation—requiring only user interaction with a crafted file—makes this a viable vector for targeted attacks and general disruption campaigns.

Affected systems

Foxit PDF Editor and Foxit PDF Reader on Microsoft Windows are confirmed affected. The vulnerability's scope is limited to local attack scenarios; network-based exploits are not possible. Windows is listed as an affected vendor/product, indicating the issue may also involve Windows-specific memory handling semantics. Organizations should verify the exact affected versions against Foxit's official advisory, as patch availability and version boundaries have not been confirmed in this analysis.

Exploitability

Exploitation requires crafting a PDF containing JavaScript that executes page deletion and attachment annotation removal in a specific sequence, then delivering it to a target user. No authentication, elevated privileges, or prior system compromise is required. The user interaction requirement (opening the PDF) is the sole technical barrier, making this suitable for phishing or watering-hole campaigns. The low attack complexity and straightforward trigger mechanism suggest that proof-of-concept code may emerge rapidly following public disclosure. However, the vulnerability does not enable code execution or privilege escalation in its immediate form—it reliably crashes the application.

Remediation

Patch your Foxit PDF Editor and Foxit PDF Reader installations to the latest available version. Verify patch availability directly from Foxit's official security advisories, as version numbers are not provided here. As an interim control, restrict PDF execution of JavaScript or disable JavaScript rendering altogether in Foxit settings if your workflow permits. Additionally, educate users not to open PDF files from untrusted sources, and consider implementing email gateway controls to block executables and suspicious document types. For critical workflows, isolate Foxit instances in sandboxed environments or air-gapped systems until patches are confirmed and deployed.

Patch guidance

Consult Foxit's official security bulletin for CVE-2026-57252 to identify the patched versions for both PDF Editor and PDF Reader. Download patches only from Foxit's official website or trusted distribution channels. Test patches in a non-production environment before enterprise deployment to ensure compatibility with existing workflows and plugins. If your organization uses Foxit in a managed environment, coordinate patching through your endpoint management system to ensure comprehensive coverage. Document your patch timeline and verify successful updates across all affected systems.

Detection guidance

Monitor for Foxit application crashes in your Windows event logs (Application log, source Foxit) that coincide with PDF file access, particularly from untrusted or external sources. Endpoint Detection and Response (EDR) tools may flag memory corruption patterns typical of use-after-free exploits. If available, configure Foxit logging to capture JavaScript execution and file operation details. Network-based detection is limited; focus on behavioral signals such as unexpected Foxit process terminations, especially when correlated with email delivery or file-share access events. Threat hunting should prioritize users who received unsolicited PDFs or downloaded files from public sources in the days prior to crashes.

Why prioritize this

This vulnerability merits immediate remediation due to its HIGH CVSS score, low attack complexity, and practical exploitability via social engineering. Although it does not currently appear on CISA's Known Exploited Vulnerabilities (KEV) catalog, the simplicity of crafting a malicious PDF and the ubiquity of email-based PDF delivery create credible risk of active exploitation. Organizations with high-volume PDF intake (legal, compliance, finance) face elevated risk. The use-after-free condition, while currently manifesting as denial of service, poses latent risk for more severe exploitation in the future as attackers refine techniques.

Risk score, explained

The CVSS 3.1 score of 7.8 reflects the combination of local attack vector (requiring user interaction), low complexity, no privileges required, and impact to all three CIA triad pillars. While the immediate manifestation is application crash (availability impact), the use-after-free nature of the defect means that confidentiality and integrity impacts are theoretically possible through memory corruption. The score appropriately penalizes the user interaction requirement but credits the ease of exploitation and the breadth of potential impact. In practical terms, this is a high-priority patch candidate for any organization deploying Foxit products.

Frequently asked questions