CVE-2026-34621: Adobe Acrobat and Reader Prototype Pollution Vulnerability
Adobe · Acrobat and Reader · NVD published 2026-04-11 · posted 2026-04-13 · last modified 2026-08-28
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.
| Weakness | CWE-1321 |
|---|---|
| CVSS vector | CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H (source: [email protected]) |
| CISA due date | 2026-04-27 (for US federal agencies under BOD; a good deadline for everyone) |
| ATT&CK tactics | n/a |
Exploitation evidence
First exploit evidence seen: 2026-04-13 (earliest date across the sources below).
Exploited in the wild
- CISA KEV: listed since 2026-04-13. Source
Public exploit code
GitHub proof-of-concept repositories
5 public repositories from 4 accounts, first seen 2026-04-13. Most starred: azefzafyoussef/CVE-2026-34621 (26 stars), view repository.
Verify before running: public PoCs can be malicious. Read the code and only run it in an isolated lab. A PoC means exploit code is public, not that this CVE is exploited in the wild.
Sources: CISA KEV · nomi-sec/PoC-in-GitHub.
No ATT&CK techniques could be mapped or inferred for this CVE yet.
How to fix it
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. (source: CISA KEV)
Fixed versions
- adobe acrobat dc: upgrade to 26.001.21411 or later
- adobe acrobat reader dc: upgrade to 26.001.21411 or later
- adobe acrobat: upgrade to 24.001.30362 or later (affected from 24.0.0)
- adobe acrobat: upgrade to 24.001.30360 or later (affected from 24.0.0)
Derived from the NVD CPE configuration (versionEndExcluding / versionEndIncluding). Always confirm with the vendor advisory.
Vendor advisories and patches
- https://helpx.adobe.com/security/products/acrobat/apsb26-43.html (CISA KEV notes)
Detection Generic guidance
Response checklist Generic guidance
- Inventory: find every instance of the affected product and version (include internet-facing and forgotten ones).
- Patch or mitigate per the vendor advisory; if you cannot patch, remove internet exposure or apply the vendor workaround.
- Assume compromise if the system was exposed before patching: hunt for the indicators in the advisory and review logs back to the disclosure date.
- Rotate credentials and secrets stored on or used by the affected system if compromise cannot be ruled out.