---
title: "CVE-2026-34621: Adobe Acrobat and Reader Prototype Pollution Vulnerability"
url: https://erroneo.us/security/cve/CVE-2026-34621/
description: "CVE-2026-34621 (Adobe Acrobat and Reader): Exploited in the wild (CISA KEV). Acrobat Reader versions 24.001.30356, 26.001.21367 and earlier are affected by…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-04-11
date_modified: 2026-08-27
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-34621"
kev: true
cvss: 8.6
epss: 0.02183
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-34621: Adobe Acrobat and Reader Prototype Pollution Vulnerability

**Signal:** Exploited: patch now if you run it. CISA has confirmed exploitation in the wild. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Yes, if you run Adobe Acrobat and Reader. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2026-04-13, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2026-04-27 ; treat that as the outer limit, not the target.
- EPSS 2.2% , percentile 82: FIRST’s model estimates a 2.2% chance of exploitation activity in the next 30 days, higher than 82% of all scored CVEs (elevated). EPSS is a probability, not a verdict.
- Needs local access needed. Lower urgency for most teams unless an attacker could already run code on the machine.

## 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.

## Affected products (CVE record)

- Adobe Acrobat DC: <= 26.001.21367
- Adobe Acrobat Reader DC: <= 26.001.21367
- Adobe Acrobat 2024: <= 24.001.30356

## Severity

- adobe CVSS 3.1: 8.6 `CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H`

## Exploitation

- CISA KEV: added 2026-04-13; federal due date 2026-04-27. Known ransomware use: Unknown.
- 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.
- CISA SSVC assessment: exploitation active , automatable no , technical impact total .
- FIRST EPSS (model of 2026-10-21): 2.18% probability of exploitation activity in the next 30 days; percentile 82.

## Sources

- [helpx.adobe.com](https://helpx.adobe.com/security/products/acrobat/apsb26-43.html)
- [CVE.org record CVE-2026-34621](https://www.cve.org/CVERecord?id=CVE-2026-34621)
- [NVD entry CVE-2026-34621](https://nvd.nist.gov/vuln/detail/CVE-2026-34621)
- [CISA Known Exploited Vulnerabilities catalog entry](https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-34621)

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Source page: https://erroneo.us/security/cve/CVE-2026-34621/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt