Executive brief
Adobe Acrobat Reader contains a vulnerability in how it validates digital certificates used to verify document signers. An attacker could exploit this flaw to forge a digital signature and impersonate a trusted signer, making a malicious document appear legitimate. This could lead to unauthorized actions or acceptance of fraudulent documents if a user relies on the signature verification feature.
Technical details
The vulnerability is an improper certificate validation flaw affecting Acrobat Reader's digital signature verification functionality. An attacker can exploit this weakness to spoof the identity of a legitimate signer by circumventing the certificate validation checks. Exploitation requires user interaction (opening a specially crafted PDF with a forged signature). The security impact is a bypass of a key security feature (signature verification), allowing the attacker to impersonate trusted signers and potentially distribute malicious documents that appear legitimate.
Affected products
- Adobe Acrobat Reader 24.001.30307, 24.001.30308, 25.001.21265 and earlier
Timeline
- 2026-03-10: disclosed: CVE-2026-27221 published