Adobe · Acrobat and Reader
CVE-2026-34621
Acrobat Reader | Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') (CWE-1321)
What it is
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.
CISA: Adobe Acrobat and Reader contain a prototype pollution vulnerability that allows for arbitrary code execution.
What to do
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Deadline for US federal agencies: April 27, 2026
More exploited flaws from Adobe
| Added | Vulnerability | Product | Severity | Attack chance |
|---|---|---|---|---|
| May 20, 2026 | Heap-Based Buffer Overflow | Acrobat and Reader | High 8.8 | 87% |
| Oct 10, 2023 | Use-After-Free | Acrobat and Reader | High 7.8 | 59% |
| Sep 14, 2023 | Out-of-Bounds Write | Acrobat and Reader | High 7.8 | 6.7% |
| Jun 8, 2022 | Buffer Overflow | Acrobat and Reader | High 7.8 | 87% |
| Jun 8, 2022 | Unspecified | Acrobat and Reader | High 8.8 | 38% |
| Jun 8, 2022 | Universal 3D Remote Code Execution | Acrobat and Reader | High 8.8 | 83% |
| Jun 8, 2022 | Use-After-Free | Acrobat and Reader | High 7.8 | 82% |
| Jun 8, 2022 | Stack-Based Buffer Overflow | Acrobat and Reader | High 7.3 | 81% |
Sources: Known Exploited Vulnerabilities (CISA, public domain), CVE records (cve.org) and EPSS (FIRST). The chance of attacks is the EPSS estimate that someone will try to exploit the flaw in the next 30 days.