CVE-2026-91814: Security vulnerability: Foxit PDF Editor/Reader Fails to Detect Modifications to Signed Documents Displaying Newly Added Content
A signature validation vulnerability exists in Foxit PDF Editor/Reader’s handling of incrementally updated PDF documents. Changes to visible document content may not invalidate the existing signature, allowing attackers to alter signed content and potentially carry out content spoofing while the document continues to appear validly signed.
Affected Software
Event History
Frequently Asked Questions
What must an attacker do to exploit this issue?
The attacker must modify a signed PDF using an incremental update that adds or changes visible content, then persuade a user to open the altered document in Foxit PDF Editor or Reader. User interaction is required.
What is the likely impact if exploitation succeeds?
Modified visible content can continue to appear covered by a valid signature, enabling content spoofing. The provided impact assessment identifies integrity impact only; no confidentiality or availability impact is stated.
Are unauthenticated remote attacks possible without user involvement?
No. The vector is network-based and requires no attacker privileges, but exploitation has high attack complexity and requires user interaction.