PT-2021-4968 · Adobe · Acrobat Reader

Published 2021-09-14 · Updated 2021-10-06 · CVE-2021-39837

Positive Technologies (AI Summary)

CVSS v3.1

7.8

High

Base vector

AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Name of the Vulnerable Software and Affected Versions Adobe Acrobat Reader DC versions 2021.005.20060 and earlier Adobe Acrobat Reader DC versions 2020.004.30006 and earlier Adobe Acrobat Reader DC versions 2017.011.30199 and earlier

Description A use-after-free vulnerability exists in the processing of the AcroForm deleteItemAt action, which could result in arbitrary code execution in the context of the current user. Exploitation of this issue requires user interaction, where a victim must open a malicious file. The vulnerability allows an attacker to execute arbitrary code using a specially crafted PDF file.

Recommendations For Adobe Acrobat Reader DC versions 2021.005.20060 and earlier, update to a version later than 2021.005.20060 to resolve the issue. For Adobe Acrobat Reader DC versions 2020.004.30006 and earlier, update to a version later than 2020.004.30006 to resolve the issue. For Adobe Acrobat Reader DC versions 2017.011.30199 and earlier, update to a version later than 2017.011.30199 to resolve the issue. As a temporary workaround, consider avoiding the use of the deleteItemAt action in AcroForm until a patch is available.

Fix

Use After Free

Weakness Enumeration

CWE-416

Related Identifiers

BDU:2021-05722

CVE-2021-39837

ZDI-21-1099

Affected Products

Acrobat Reader

References · 7

• https://nvd.nist.gov/vuln/detail/CVE-2021-39837 · Security Note
• https://osv.dev/vulnerability/CVE-2021-39837 · Vendor Advisory
• https://zerodayinitiative.com/advisories/ZDI-21-1099 · Security Note
• https://bdu.fstec.ru/vul/2021-05722 · Security Note
• https://helpx.adobe.com/security/products/acrobat/apsb21-55.html · Vendor Advisory
• https://safe-surf.ru/specialists/bulletins-nkcki/669565 · Security Note
• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-39837 · Note