CVE-2026-34621 is a prototype pollution vulnerability in Adobe Acrobat Reader that affects versions 24.001.30356, 26.001.21367 and earlier. This vulnerability allows improper modification of object prototype attributes, which can lead to arbitrary code execution in the context of the current user. Exploitation requires that a victim open a malicious file, indicating user interaction is necessary. The vulnerability has a CVSS 3.1 base score of 8.6, reflecting high impact on confidentiality, integrity, and availability. No vendor advisory or patch information is currently available, and the product is not a cloud service.

Successful exploitation of this vulnerability could result in arbitrary code execution with the privileges of the current user, potentially leading to full compromise of the user's environment. The attack requires user interaction by opening a malicious file. There are no known active exploits in the wild at this time.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, users should exercise caution when opening files from untrusted sources and consider applying any available security controls to limit the impact of potential exploitation.