Foxit PDF Reader FoxitUpdater Improper Certificate Validation Local Privilege Escalation Vulnerability

September 23rd, 2026
ZDI-26-741 ZDI-CAN-32452

CVE ID

CVE-2026-91812

CVSS Score

7.1 AV:A/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected Vendors

Foxit

Affected Products

PDF Reader

Vulnerability Details

This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of Foxit PDF Reader. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.

The specific flaw exists within the update functionality. The issue results from the lack of proper validation of the certificate presented by the server. An attacker can leverage this vulnerability to execute arbitrary code in the context of SYSTEM.

Additional Details

Foxit has issued an update to correct this vulnerability. More details can be found at:
https://www.foxit.com/support/security-bulletins.html

Disclosure Timeline

  • 2026-08-20 - Vulnerability reported to vendor
  • 2026-09-23 - Coordinated public release of advisory
  • 2026-09-23 - Advisory Updated

Credit

praydog & kmx00

Back to Advisories