Acrobat Reader 24/26 Prototype Pollution ARC
CVE-2026-34621 Published on April 11, 2026
Acrobat Reader | Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') (CWE-1321)
Acrobat Reader versions 24.001.30356, 26.001.21367 and earlier are affected by an Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') vulnerability that could result in arbitrary code execution in the context of the current user. Exploitation of this issue requires user interaction in that a victim must open a malicious file.
Known Exploited Vulnerability
This Adobe Acrobat and Reader Prototype Pollution Vulnerability is part of CISA's list of Known Exploited Vulnerabilities. Adobe Acrobat and Reader contain a prototype pollution vulnerability that allows for arbitrary code execution.
The following remediation steps are recommended / required by April 27, 2026: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Vulnerability Analysis
CVE-2026-34621 can be exploited with local system access, requires user interaction. This vulnerability is considered to have a low attack complexity. This vulnerability is known to be actively exploited by threat actors. The potential impact of an exploit of this vulnerability is considered to be very high.
Weakness Type
What is a Prototype Pollution Vulnerability?
The software receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.
CVE-2026-34621 has been classified to as a Prototype Pollution vulnerability or weakness.
Products Associated with CVE-2026-34621
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Affected Versions
Adobe Acrobat Reader:- Before and including 26.001.21367 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.