CVE-2026-91788 Foxit CVE debrief

Who should care

Defenders responsible for managing and securing PDF Editor and Reader installations, especially in environments where untrusted PDFs are opened, should assess exposure and take necessary actions.

Why it matters

CVE-2026-91788 is a medium-severity vulnerability in Foxit PDF Editor and Reader that allows malicious PDFs to access sensitive content. Defenders should assess exposure, verify versions, and implement security measures to restrict access and monitor activity.

• Potential unauthorized access to sensitive content
• Possible data exfiltration through malicious PDFs
• Need for verification of affected versions and updates
• Importance of monitoring for suspicious PDF-related activity

Technical summary

The vulnerability is caused by the lack of attribute authorization checks in the JavaScript interface implementation of Foxit PDF Editor and Reader. This allows a malicious PDF to access sensitive content from other documents within the same process and transmit it externally. The vulnerability has a CVSS score of 4.7 and is considered medium-severity. Affected versions of Foxit PDF Editor and Reader are vulnerable to this issue. Defenders should assess exposure, verify versions, and implement security measures to restrict access and monitor activity.

Defensive priority

Defenders should prioritize assessing exposure in environments where Foxit PDF Editor or Reader are used, especially in contexts where untrusted PDFs are opened.

Recommended defensive actions

• Assess exposure in environments where Foxit PDF Editor or Reader are used
• Verify if the installed versions are affected and update to a fixed version if necessary
• Implement additional security measures to restrict access to sensitive content
• Monitor for suspicious activity related to PDF files
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, including its CVSS score of 4.7 and the affected versions of Foxit PDF Editor and Reader. The vulnerability is caused by the lack of attribute authorization checks in the JavaScript interface implementation of Foxit PDF Editor and Reader. This allows a malicious PDF to access sensitive content from other documents within the same process and transmit it externally. Defenders should verify versions, implement security measures to restrict access, and monitor for The N

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.