FalehSec Exploited-vulnerability triage · joined from CISA KEV, NVD CVSS and EPSS

CVE-2026-34621

Adobe · Acrobat and Reader · Adobe Acrobat and Reader Prototype Pollution Vulnerability

Verdict
Patch on your normal cycle · actively exploited, not reachable unauthenticated from the internet, and in the top 25% of CVEs by near-term exploitation probability

Added to CISA KEV 2026-04-13 · exploited in the wild for 167 days

What an attacker can reach How likely Time What CISA says to do Sources All 545

What an attacker can reach

CVSS 8.6 HIGH. The score is a summary; these three components are the part that decides whether something scanning the internet can use it.

Attack vectorlocalrequires local access to the machine
Privileges requirednoneneeds no credentials at all
User interactionrequiredneeds a user to click, load or submit something first
Base vectorCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
WeaknessCWE-1321

This describes the vulnerability. It says nothing about whether your systems run it.

How likely

EPSS puts the probability of exploitation in the next 30 days at 0.0218, which places it in the top 25% of all tracked CVEs. The percentile is the more useful half: 0.18 in absolute terms sounds low until you know most of the internet-facing software in the world scores under that.

EPSS probability0.0218
Percentile0.816 — top 25%

Time

Added to KEV2026-04-13
Days exploited167
Federal remediation duenot set
Ransomware useno known ransomware campaign use

What CISA says 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.

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.

Sources