CVE-2026-34621 | Acrobat Reader | Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') (CWE-1321)

Exp

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.

Published: 2026-04-11 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-34621 is rated Critical Active Threat (88.1/100): CVSS High severity, with high exploitation likelihood (EPSS 7.09%, 93th percentile). CISA KEV confirms active exploitation (added 2026-04-13) affecting Adobe / Acrobat and Reader. a weakness (CWE-1321) Unauthenticated remote administrative access may be possible. The CISA remediation deadline has passed—treat as an emergency patch priority.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

CISA KEV Record for CVE-2026-34621

Name: Adobe Acrobat and Reader Prototype Pollution Vulnerability · CISA KEV detail

Exploit added: 2026-04-13

Action due: 2026-04-27

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.

Exploit prediction scoring system (EPSS) score for CVE-2026-34621

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 11.03% 7.09% -3.95%
2 2026-06-08 9.66% 11.03% +1.37%
3 2026-06-06 — 9.66% —

Full EPSS history (16 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-34621

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.6 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 6.0 [email protected]

Weakness enumeration for CVE-2026-34621

Affected software / configurations for CVE-2026-34621

Vendor Product Version Raw CPE
adobe acrobat_dc < 26.001.21411 cpe:2.3:a:adobe:acrobat_dc:*:*:*:*:continuous:*:*:*
adobe acrobat_reader_dc < 26.001.21411 cpe:2.3:a:adobe:acrobat_reader_dc:*:*:*:*:continuous:*:*:*
adobe acrobat >= 24.0.0, < 24.001.30362 cpe:2.3:a:adobe:acrobat:*:*:*:*:classic:*:*:*
adobe acrobat >= 24.0.0, < 24.001.30360 cpe:2.3:a:adobe:acrobat:*:*:*:*:classic:*:*:*

References for CVE-2026-34621

cvelogic Threat Intelligence