CVE-2024-39422: Adobe Acrobat RCE Vulnerability

CVE-2024-39422 Overview

CVE-2024-39422 is a Use After Free vulnerability [CWE-416] affecting multiple versions of Adobe Acrobat and Acrobat Reader on Windows and macOS. The flaw impacts Acrobat Reader 20.005.30636, 24.002.20965, 24.002.20964, 24.001.30123, and earlier releases. An attacker who convinces a user to open a crafted PDF can achieve arbitrary code execution in the context of the current user. Adobe addressed the issue in security advisory APSB24-57.

Critical Impact
Successful exploitation yields arbitrary code execution with the privileges of the user opening the malicious document, enabling local compromise of the endpoint.

Affected Products

Adobe Acrobat and Acrobat DC (Classic and Continuous tracks) through the versions listed above
Adobe Acrobat Reader and Acrobat Reader DC (Classic and Continuous tracks) through the versions listed above
Microsoft Windows and Apple macOS installations running the affected Acrobat builds

Discovery Timeline

2024-08-14 - CVE-2024-39422 published to the National Vulnerability Database
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-39422

Vulnerability Analysis

CVE-2024-39422 is a Use After Free condition in the PDF parsing and rendering logic of Adobe Acrobat and Acrobat Reader. The application references a heap object after that object has been freed, allowing attacker-controlled data to occupy the reclaimed memory. When the dangling pointer is dereferenced, control flow can be redirected into attacker-supplied content.

Exploitation requires user interaction: the victim must open a malicious PDF. The attack executes locally within the process boundary of Acrobat or Reader, so any code executed inherits the privileges of the current user. This is consistent with Adobe's classification of the issue as arbitrary code execution under advisory APSB24-57.

Root Cause

The root cause is improper object lifetime management inside Acrobat's document handling routines. A code path releases a memory allocation while another code path retains a reference to it. Crafted PDF structures trigger the sequence needed to reach the stale pointer, which is then reused with attacker-influenced contents.

Attack Vector

The attack vector is local and file-based. An attacker delivers a malicious PDF through email, chat, a compromised website, or a shared drive. When the user opens the document in a vulnerable Acrobat or Reader build, parsing of the crafted objects triggers the use-after-free and leads to code execution as the current user. No network exposure of the reader is required, and no elevated privileges are needed to launch the exploit.

No public proof-of-concept or exploit code is available for CVE-2024-39422 at the time of publication, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog. Refer to the Adobe Security Advisory APSB24-57 for vendor technical details.

Detection Methods for CVE-2024-39422

Indicators of Compromise

Unexpected child processes spawned by Acrobat.exe or AcroRd32.exe, particularly command interpreters such as cmd.exe, powershell.exe, or wscript.exe
Acrobat processes writing executable content to user-writable directories such as %APPDATA%, %TEMP%, or ~/Library/Caches
Outbound network connections initiated by an Acrobat process shortly after a PDF is opened
Crash telemetry or Windows Error Reporting entries for Acrobat modules referencing heap corruption or access violations

Detection Strategies

Hunt for Acrobat process trees that deviate from normal document rendering behavior, such as reader processes loading unusual DLLs or invoking scripting hosts
Deploy behavioral endpoint detection that flags exploitation patterns like ROP execution and shellcode staging from PDF readers
Inspect email and web gateways for PDFs containing malformed object streams, embedded JavaScript, or unusual cross-reference structures

Monitoring Recommendations

Alert on Acrobat process versions still reporting vulnerable builds (20.005.30636, 24.002.20965, 24.002.20964, 24.001.30123, and earlier) via software inventory
Forward Acrobat process and file telemetry to a central data lake for retrospective hunting across historical PDF opens
Track EPSS movement for CVE-2024-39422, currently around the 86th percentile, and adjust prioritization if exploit activity emerges

How to Mitigate CVE-2024-39422

Immediate Actions Required

Apply the Adobe updates published in advisory APSB24-57 to all Windows and macOS endpoints running Acrobat or Reader
Identify systems still running the vulnerable builds and prioritize patching for users who routinely handle external PDFs
Restrict opening of PDFs from untrusted sources until patch coverage is confirmed enterprise-wide
Reinforce user awareness that opening unsolicited PDF attachments is the required trigger for exploitation

Patch Information

Adobe released fixed versions in Adobe Security Advisory APSB24-57. Upgrade Acrobat DC and Acrobat Reader DC on the Continuous track, and Acrobat and Acrobat Reader on the Classic track, to the versions specified in that bulletin. Enable automatic updates in the Acrobat preferences to reduce future exposure windows.

Workarounds

Enable Protected View and Protected Mode (sandbox) in Acrobat and Reader to constrain the impact of exploitation attempts
Disable JavaScript execution within Acrobat via Preferences > JavaScript where business processes allow
Block or quarantine PDFs originating from external senders at the email gateway when patch rollout is incomplete
Enforce application allowlisting to prevent Acrobat from launching untrusted child processes

bash

# Windows registry example: disable JavaScript in Acrobat/Reader for enterprise fleets
reg add "HKCU\Software\Adobe\Acrobat Reader\DC\JSPrefs" /v bEnableJS /t REG_DWORD /d 0 /f
reg add "HKCU\Software\Adobe\Adobe Acrobat\DC\JSPrefs" /v bEnableJS /t REG_DWORD /d 0 /f