Adobe Patches Actively Exploited Acrobat Flaw CVE-2026-34621
Summary
Adobe patched CVE-2026-34621, a prototype pollution flaw in Acrobat and Acrobat Reader that can enable arbitrary code execution. Adobe acknowledged active exploitation and released fixes for affected Windows and macOS versions.
Key points
- Adobe acknowledged that CVE-2026-34621 is being actively exploited in the wild.
- The JavaScript prototype pollution flaw can enable arbitrary code execution when a specially crafted PDF is opened.
- Acrobat DC and Acrobat Reader DC versions up to 26.001.21367 are affected; Adobe fixed them in build 26.001.21411.
- Acrobat 2024 versions up to 24.001.30356 are affected; fixes are in 24.001.30362 for Windows and 24.001.30360 for macOS.
- The article reports a CVSS score of 8.6 and says Adobe revised the attack vector from Network to Local.
- Researcher Haifei Li and EXPMON disclosed the flaw; evidence cited in the article suggests exploitation may date to December 2025.
Article Details
- Vulnerability Types
- JavaScript prototype pollution
- Severity
- Critical; CVSS 8.6
- Affected Versions
- Acrobat DC 26.001.21367 and earlier
- Acrobat Reader DC 26.001.21367 and earlier
- Acrobat 2024 24.001.30356 and earlier
- Exploitation Status
- active
- Exploit Availability
- unknown
- Patch Status
- available
MITRE ATT&CK
T1059.007 · JavaScriptThe exploit runs malicious JavaScript when a specially crafted PDF is opened in Adobe Reader.T1203 · Exploitation for Client ExecutionThe flaw is actively exploited to execute malicious code in affected Acrobat installations.T1204.002 · Malicious FileThe described exploitation is triggered when a user opens a specially crafted PDF.
CVE
People
Vendors
Products
Acrobat 2024The flaw is a JavaScript prototype pollution issue that can lead to arbitrary code execution and affects multiple Acrobat DC and Acrobat 2024 builds disclosed by EXPMON researcher Haifei Li.Acrobat DCThe flaw is a JavaScript prototype pollution issue that can lead to arbitrary code execution and affects multiple Acrobat DC and Acrobat 2024 builds disclosed by EXPMON researcher Haifei Li.Acrobat Reader DCAffected products include Acrobat DC and Acrobat Reader DC up to 26.001.21367 and Acrobat 2024 up to 24.001.30356, with fixes in later builds.