Sun, 12 Apr 2026
← BackAdobe released emergency patches for a critical Acrobat and Reader zero-day exploited in the wild. The vulnerability allows arbitrary code execution.
Adobe on Saturday released emergency patches for a critical Acrobat and Reader zero-day that has been exploited in the wild for several months. The vulnerability has been assigned the CVE identifier CVE-2026-34621 and a CVSS score of 9.6. According to the software giant, the flaw stems from improperly controlled modifications to prototype attributes and can be exploited to execute arbitrary code. Acrobat and Reader for Windows and macOS are affected.
Patches are included in version 26.001.21411 of Acrobat DC and Acrobat Reader DC, and versions 24.001.30362 and 24.001.30360 of Acrobat 2024. Adobe’s advisory confirms that CVE-2026-34621 has been exploited in the wild. The company has credited Haifei Li for reporting the vulnerability. Li is a reputable researcher who has worked at Fortinet, McAfee, Microsoft, and Check Point.
He is the founder of Expmon, a sandbox system designed to detect file-based exploits. Li came across the zero-day while analyzing a sophisticated PDF exploit uploaded to Expmon. The exploit he identified was designed to harvest information, but the researcher warned in his initial disclosure that subsequent stages in the exploit chain may include remote code execution and a sandbox escape.