CVE-2026-91792 in PDF Editor
Summary
by MITRE • 09/23/2026
When processing a specially crafted PDF, Foxit PDF Editor/Reader may perform reentrant zoom and layout operations through page- and annotation-related JavaScript actions. This can cause the application to access page objects after they have been released, resulting in a use-after-free condition and an application crash.
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Analysis
by VulDB Data Team • 09/23/2026
The vulnerability described involves a critical memory management flaw within Foxit PDF Editor and Reader, specifically triggered by the processing of maliciously crafted Portable Document Format files. The root cause lies in how the application handles JavaScript actions associated with page elements and annotations during rendering operations. When an attacker constructs a PDF document containing specific JavaScript triggers linked to zoom or layout events, the software initiates reentrant execution paths that disrupt normal memory lifecycle management. This scenario creates a race condition where internal objects are deallocated while still being referenced by active processes within the application's runtime environment.
From a technical perspective, this flaw manifests as a use-after-free vulnerability, which is categorized under CWE-416 in the Common Weakness Enumeration standard. The core issue arises because the JavaScript engine or layout renderer attempts to access page objects that have already been released from memory due to premature deallocation during reentrant zoom operations. This invalid memory access leads directly to application instability and crashes, representing a denial of service against users attempting to view these malicious documents. In some contexts, if the corrupted heap state can be precisely controlled through further exploitation techniques beyond simple crashing, such vulnerabilities may also serve as stepping stones for arbitrary code execution, although the primary reported impact here is stability-related.
The operational impact of this vulnerability extends beyond mere application crashes. For end-users, it results in a loss of productivity and potential data loss if unsaved work is present when the software terminates unexpectedly. From an organizational security standpoint, this flaw highlights risks associated with document ingestion workflows where PDFs are processed automatically or viewed by multiple users. Attackers can distribute these crafted files via email attachments, malicious websites, or shared network drives to exploit unsuspecting individuals who open the documents using vulnerable versions of Foxit software.
Mitigation strategies should focus on both immediate remediation and long-term defensive posture improvements. Users must ensure that their installation of Foxit PDF Editor and Reader is updated to the latest version provided by the vendor, as patches for this specific use-after-free condition have likely been released following disclosure. Additionally, organizations should implement application whitelisting or sandboxing solutions to restrict the privileges granted to document viewers, thereby limiting the potential impact if an exploit attempt occurs. Security awareness training regarding suspicious PDF attachments and enabling protected view modes that isolate rendering processes from the main application memory space can further reduce exposure to such client-side attacks aligned with MITRE ATT&CK techniques involving malicious file execution or exploitation of software vulnerabilities during initial access phases.