IRONSMITHINTEL
HIGHCVSS8.6
|
Actively Exploited
|CISA KEV|CVE-2026-34621|Auth: none — unauthenticated|Reboot: required|Manual only

Adobe Acrobat and Reader Prototype Pollution Vulnerability

Adobe Acrobat and Reader contain a prototype pollution vulnerability that allows for arbitrary code execution.

Published Apr 11, 2026 · Updated May 16, 2026
Why patchRisk explained in plain English
Worst-case scenarioIf unpatched

A local attacker, without authentication, can achieve full data confidentiality loss, arbitrary modification of data, complete denial of service or system unavailability. Federal agencies are required to remediate by 2026-04-27 under CISA BOD 22-01.

How the attack worksNo clicks needed

This is a Software Vulnerability (CWE-1321) (CWE-1321) vulnerability in Adobe Acrobat and Reader. 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. Exploitation requires local access, low attack complexity, no authentication required, and user interaction required.

Am I affected?Quick check

Probably yes if any of these apply:

Endpoint Administrators
IT Security
Running acrobat dc: v < 26.001.21411; acrobat reader dc: v < 26.001.21411; acrobat: 24.0.0 ≤ v < 24.001.30362, 24.0.0 ≤ v < 24.001.30360
Real-world incidentsWhat we've seen

CISA added this CVE to the Known Exploited Vulnerabilities catalog on 2026-04-13 based on evidence of active exploitation in the wild. Federal agencies required to remediate by 2026-04-27.

How to patch

Manual remediation steps

Apply the Vendor Patch

This vulnerability is in the CISA Known Exploited Vulnerabilities catalog — apply the vendor's security update as soon as possible.

CISA required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

References

    1
    Vendor advisory: https://helpx.adobe.com/security/products/acrobat/apsb26-43.html
    1
    NVD entry: https://nvd.nist.gov/vuln/detail/CVE-2026-34621
    1
    CISA KEV: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-34621
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