CVE-2026-57258: Foxit PDF Editor PRC File Out-of-Bounds Read Vulnerability

Technical summary

CVE-2026-57258 is an out-of-bounds read vulnerability in PRC (Printer Command) file header parsing logic. The vulnerability exists because the parsing routine assumes array contents exist based on structure description fields in the file header without proper bounds checking. CWE-125 (Out-of-bounds Read) applies. When a malformed PRC file is processed, memory outside the intended buffer is accessed, causing application termination or leaking sensitive data from adjacent memory. The issue is triggered during file load, making it accessible to any user who opens an untrusted file.

Business impact

For organizations relying on Foxit PDF Editor or Reader for document workflows, this vulnerability creates a denial-of-service risk. An attacker could distribute a malicious PRC file via email or document repository, causing the application to crash and disrupting user productivity. The information disclosure component means confidential data resident in memory could potentially be exposed to an attacker with local access. This is particularly concerning in environments where PDF tools are widely used for handling sensitive materials. The requirement for user interaction limits enterprise-wide exploitation but makes targeted phishing campaigns viable.

Affected systems

Foxit PDF Editor and Foxit PDF Reader are directly vulnerable. The advisory also lists Microsoft Windows and Apple macOS as affected platforms, likely because these operating systems' native components or integrations may be involved in PRC handling. Organizations should inventory PDF editor usage and verify which versions are deployed. The exact affected version ranges should be confirmed against Foxit's official security advisory and Windows/macOS security bulletins.

Exploitability

Exploitation requires crafting a malicious PRC file and convincing a user to open it, making this a user-interaction attack vector. The CVSS vector (AV:L/AC:L/PR:N/UI:R/S:U) confirms that local access and user action are prerequisites. There is no evidence of public exploit code or active exploitation at this time. The attack is straightforward in principle—no special privileges or complex conditions are needed—but depends entirely on social engineering or file distribution tactics. Automated scanning cannot detect exploitation; detection relies on identifying malicious files before user interaction.

Remediation

Apply security updates from Foxit for PDF Editor and Reader as soon as they become available. Verify patch versions through official Foxit security advisories and apply them to all affected installations. For Windows and macOS, check vendor security bulletins for related patches. In the interim, implement application controls to restrict PRC file handling, educate users to avoid opening unexpected file attachments or files from untrusted sources, and consider disabling PRC support if not operationally necessary. Monitor for unusual application crashes related to PDF tool usage.

Patch guidance

Contact Foxit's support channels and consult their security advisories for the specific patched versions of PDF Editor and Reader addressing CVE-2026-57258. Apply updates through your organization's software deployment pipeline, prioritizing systems where PDF editing is critical to operations. Verify compatibility with your existing document workflows before mass deployment. For Windows and macOS, ensure your systems are updated to the latest stable releases; consult Microsoft Security Update Guide and Apple Security Updates for coverage details. Test patches in a non-production environment first.

Detection guidance

Monitor for application crashes or hangs when opening PRC files, which may indicate exploitation attempts. File integrity monitoring can help detect unexpected PRC files appearing on systems. Endpoint detection and response (EDR) tools should flag unusual memory access patterns or crashes in PDF editor processes tied to file opening operations. In environments with document capture or scanning, implement file-type validation to reject or quarantine unexpected PRC files. Review logs for failed application launches or unusual memory violations tied to Foxit processes. User education about not opening unexpected file attachments is a critical detective control.

Why prioritize this

Although scored as MEDIUM severity (CVSS 6.1), this vulnerability warrants prioritized patching because it affects widely deployed PDF editing tools in many organizations. The out-of-bounds read can leak sensitive data from memory, posing confidentiality risks in environments handling regulated documents. The low attack complexity and lack of privilege requirements make it an attractive vector for targeted attacks. The vulnerability is not currently in CISA's KEV catalog, suggesting lower in-the-wild exploitation pressure, but the combination of high user-interaction frequency with PDF files and memory disclosure potential justifies rapid patching cycles.

Risk score, explained

CVSS 6.1 (MEDIUM) reflects a vulnerability with moderate severity: out-of-bounds reads cause crashes (high availability impact) but require local file system access and user interaction to trigger. No network vector exists; the threat is local. Confidentiality impact is rated as low rather than high because the leaked data depends on memory state and is not guaranteed. Integrity is not affected, as the vulnerability does not allow file modification. The MEDIUM rating appropriately captures a nuisance-to-serious threat depending on organizational risk tolerance for PDF tool availability and data sensitivity in memory.

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