Zero-day vulnerability in Adobe Acrobat

Prototype pollution
CVE-2026-34621

Vulnerability details

Advisory: SB2026041109 - Remote code execution in Adobe Acrobat and Reader

Vulnerable component: Adobe Acrobat

CVE-ID: CVE-2026-34621

CVSSv3 score: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:H/RL:O/RC:C

CWE-ID: CWE-1321 - Improperly Controlled Modification of Object Prototype Attributes (\'Prototype Pollution\')

Description:

The vulnerability allows a remote attacker to execute arbitrary JavaScript code.

The vulnerability exists due to improper input validation when handling PDF files. A remote attacker can trick the victim into opening a specially crafted PDF file and execute arbitrary code on the system.

Note, the vulnerability is being actively exploited in the wild. 

External links:

https://helpx.adobe.com/security/products/acrobat/apsb26-43.html

About zero-day vulnerabilities

Zero-day vulnerability is an undisclosed vulnerability in software that hackers can exploit to compromise computer programs, gain unauthorized access to sensitive data, penetrate networks, etc. We consider vulnerability a zero-day when there is no solution provided from software vendor and the vulnerability is being actively exploited by malicious actors.

Zero-day candidate is a potential zero-day vulnerability in software which might have been used in targeted attacks, however there is no evidence to support this suggestion.