CVE-2026-21267: Adobe Dreamweaver RCE Vulnerability

CVE-2026-21267 Overview

Adobe Dreamweaver Desktop versions 21.6 and earlier are affected by an Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') vulnerability (CWE-78) that could lead to arbitrary code execution by an attacker. This vulnerability requires user interaction where a victim must open a malicious file, and the scope is changed, meaning the vulnerability can affect resources beyond the vulnerable component's security scope.

Critical Impact

Successful exploitation of this OS Command Injection vulnerability enables attackers to execute arbitrary code with the privileges of the Dreamweaver application, potentially leading to complete system compromise when a user opens a specially crafted malicious file.

Affected Products

• Adobe Dreamweaver Desktop version 21.6
• Adobe Dreamweaver Desktop versions prior to 21.6

Discovery Timeline

• January 13, 2026 - CVE-2026-21267 published to NVD
• January 13, 2026 - Last updated in NVD database

Technical Details for CVE-2026-21267

Vulnerability Analysis

This vulnerability is classified as an OS Command Injection flaw (CWE-78), where user-supplied input is improperly neutralized before being passed to operating system command execution functions. The vulnerability has a local attack vector, meaning an attacker must have local access or rely on social engineering to deliver a malicious file to the victim. However, the scope change characteristic indicates that exploitation can affect resources beyond Dreamweaver itself, potentially compromising the underlying operating system or other applications running with the same privileges.

The attack requires no special privileges from the attacker but does require user interaction—specifically, the victim must be tricked into opening a maliciously crafted file. Once opened, the injected OS commands execute with the full permissions of the Dreamweaver process.

Root Cause

The root cause of this vulnerability lies in insufficient input validation and sanitization of special characters within file content processed by Dreamweaver Desktop. When the application processes certain file types, it fails to properly neutralize shell metacharacters and command separators, allowing an attacker to embed malicious OS commands that are subsequently executed by the application.

Attack Vector

The attack vector is local, requiring an attacker to deliver a malicious file to the target system and convince the user to open it with Dreamweaver Desktop. Attack scenarios include:

1. Phishing campaigns - Sending malicious project files disguised as legitimate Dreamweaver assets via email
2. Compromised asset repositories - Uploading malicious files to shared web development resource libraries
3. Supply chain attacks - Injecting malicious content into web development templates or project archives

The malicious file contains specially crafted content with embedded OS command sequences. When Dreamweaver parses and processes this content, the unsanitized input is passed to system command execution functions, resulting in arbitrary command execution.

For detailed technical information about the vulnerability mechanism, refer to the Adobe Security Advisory APSB26-01.

Detection Methods for CVE-2026-21267

Indicators of Compromise

• Unexpected child processes spawned by Dreamweaver.exe such as cmd.exe, powershell.exe, or bash
• Unusual network connections initiated by the Dreamweaver process
• Suspicious file operations or registry modifications following Dreamweaver file operations
• Abnormal command-line arguments in processes spawned from Dreamweaver

Detection Strategies

• Monitor process creation events for shell interpreter spawning from Dreamweaver parent processes
• Implement endpoint detection rules for command injection patterns in process command lines
• Deploy file integrity monitoring on critical system directories that could be targeted post-exploitation
• Configure application whitelisting to alert on unexpected binaries executed by Dreamweaver

Monitoring Recommendations

• Enable verbose logging for Dreamweaver application activity
• Configure SIEM rules to correlate Dreamweaver file open events with subsequent suspicious process creation
• Monitor for execution of encoding/decoding utilities that may indicate command obfuscation attempts
• Track file downloads and email attachments containing Dreamweaver-associated file extensions

How to Mitigate CVE-2026-21267

Immediate Actions Required

• Update Adobe Dreamweaver Desktop to the latest patched version as soon as available from Adobe
• Educate users about the risks of opening untrusted project files or assets from unknown sources
• Implement application-level network restrictions to limit Dreamweaver's outbound connectivity
• Consider temporary restriction of Dreamweaver usage until the patch is applied in high-risk environments

Patch Information

Adobe has released security advisory APSB26-01 addressing this vulnerability. Organizations should apply the vendor-provided patch immediately. Check the Adobe Security Bulletin page for the latest patched version and download it through Adobe Creative Cloud or the official Adobe download portal.

Workarounds

• Implement strict file source policies, only allowing Dreamweaver to open files from trusted, verified sources
• Enable application sandboxing or containerization to limit the impact of potential exploitation
• Use endpoint protection solutions that can detect and block command injection attempts
• Temporarily disable or restrict macros and script execution features within Dreamweaver if available

# Example: Block suspicious child process spawning from Dreamweaver using Windows AppLocker
# Add this to your AppLocker XML policy to restrict cmd.exe spawning from Dreamweaver
# Note: Adjust paths based on your installation location

# PowerShell command to check current Dreamweaver installations
Get-ChildItem -Path "C:\Program Files\Adobe\*Dreamweaver*" -Recurse -ErrorAction SilentlyContinue

# Monitor Dreamweaver process behavior
Get-WinEvent -FilterHashtable @{LogName='Security';Id=4688} | 
  Where-Object {$_.Properties[13].Value -like "*Dreamweaver*"} |
  Select-Object TimeCreated, @{N='CommandLine';E={$_.Properties[8].Value}}