CVE-2026-34621

high

Description

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.

References

https://helpx.adobe.com/security/products/acrobat/apsb26-43.html

https://thehackernews.com/2026/04/april-patch-tuesday-fixes-critical.html

https://www.securityweek.com/organizations-warned-of-exploited-windows-adobe-acrobat-vulnerabilities/

https://www.securityweek.com/adobe-patches-55-vulnerabilities-across-11-products/

https://securityaffairs.com/190775/security/u-s-cisa-adds-adobe-fortinet-microsoft-windows-microsoft-exchange-server-and-microsoft-windows-flaws-to-its-known-exploited-vulnerabilities-catalog.html

https://www.theregister.com/2026/04/13/ransomware_gang_other_crims_attacking/

https://www.helpnetsecurity.com/2026/04/13/adobe-acrobat-reader-cve-2026-34621-emergency-fix/

https://www.darkreading.com/application-security/adobe-patches-actively-exploited-zero-day

https://www.cisa.gov/news-events/alerts/2026/04/13/cisa-adds-seven-known-exploited-vulnerabilities-catalog

https://www.bleepingcomputer.com/news/security/adobe-rolls-out-emergency-fix-for-acrobat-reader-zero-day-flaw/

https://www.securityweek.com/adobe-patches-reader-zero-day-exploited-for-months/

https://thehackernews.com/2026/04/adobe-patches-actively-exploited.html

https://securityaffairs.com/190697/security/adobe-fixes-actively-exploited-acrobat-reader-flaw-cve-2026-34621.html

https://www.theregister.com/2026/04/09/monthsold_adobe_reader_zeroday_uses/

https://www.bleepingcomputer.com/news/security/hackers-exploiting-acrobat-reader-zero-day-flaw-since-december/

https://thehackernews.com/2026/04/adobe-reader-zero-day-exploited-via.html

https://hackread.com/adobe-reader-zero-day-exploit-data-malicious-pdfs/

https://justhaifei1.blogspot.com/2026/04/expmon-detected-sophisticated-zero-day-adobe-reader.html

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-34621

Details

Source: Mitre, NVD

Published: 2026-04-11

Updated: 2026-04-13

Known Exploited Vulnerability (KEV)

Risk Information

CVSS v2

Base Score: 10

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C

Severity: Critical

CVSS v3

Base Score: 8.6

Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

Severity: High

EPSS

EPSS: 0.00235

Vulnerability Watch

Tenable Research has classified this CVE under the following Vulnerability Watch classification, which includes active and historical (inactive) classifications. You can learn more about these classifications on our blog.

Vulnerability of Interest

Detections

Analytics