CVE-2026-34621

9.5 CISA KEV

Adobe · Acrobat Reader

Adobe Acrobat Reader is vulnerable to prototype pollution, which can result in arbitrary code execution when a victim opens a malicious file.

Executive summary

A critical prototype pollution vulnerability in Adobe Acrobat Reader allows attackers to execute arbitrary code on the victim's machine through malicious file interaction.

Vulnerability

This is a prototype pollution vulnerability that allows for the modification of object attributes. Exploitation requires user interaction, specifically the opening of a malicious file, which then triggers arbitrary code execution in the user's context.

Business impact

With a CVSS score of 9.6, this is a critical vulnerability. An attacker can gain control over a user's workstation, potentially accessing sensitive documents, credentials, and internal network resources, leading to significant reputational and operational damage.

Remediation

Immediate Action: Update Adobe Acrobat Reader to the latest patched version immediately.

Proactive Monitoring: Monitor for suspicious file access patterns or unusual application behavior following the opening of unexpected documents.

Compensating Controls: Implement endpoint protection (EDR) to detect and block malicious code execution originating from PDF reader processes.

Exploitation status

Public Exploit Available: No

Analyst recommendation

Organizations should mandate that all users update Acrobat Reader to the latest version to prevent potential client-side exploitation. User awareness training regarding opening unsolicited documents is also recommended.

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History

  1. Disclosed CVE record published
  2. Published in the daily brief critical section, carried in 15 daily briefs, Apr 11 to Apr 26
  3. Fix documented version 26.001.21411 per CVE record