CVE-2026-21277
📋 TL;DR
This CVE describes a heap-based buffer overflow vulnerability in Adobe InDesign that could allow attackers to execute arbitrary code when a user opens a malicious file. The vulnerability affects InDesign Desktop versions 21.0, 19.5.5 and earlier, putting users who open untrusted InDesign files at risk.
💻 Affected Systems
- Adobe InDesign Desktop
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with attacker gaining the same privileges as the current user, potentially leading to data theft, ransomware deployment, or lateral movement within the network.
Likely Case
Local code execution leading to malware installation, credential theft, or data exfiltration from the affected workstation.
If Mitigated
No impact if users only open trusted files from verified sources and proper endpoint security controls are in place.
🎯 Exploit Status
Exploitation requires user interaction (opening malicious file). No public exploit code is currently available according to the advisory.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 21.0.1 and 19.5.6
Vendor Advisory: https://helpx.adobe.com/security/products/indesign/apsb26-02.html
Restart Required: Yes
Instructions:
1. Open Adobe Creative Cloud application 2. Navigate to 'Apps' tab 3. Find Adobe InDesign 4. Click 'Update' button 5. Restart computer after installation completes
🔧 Temporary Workarounds
Restrict InDesign file handling
allConfigure system to open InDesign files only from trusted locations or block execution of InDesign for untrusted users
🧯 If You Can't Patch
- Implement application whitelisting to prevent execution of unauthorized InDesign files
- Educate users to never open InDesign files from untrusted sources and implement email filtering for suspicious attachments
🔍 How to Verify
Check if Vulnerable:
Check InDesign version via Help > About InDesign menu. If version is 21.0, 19.5.5 or earlier, system is vulnerable.Check Version:
On Windows: Check registry at HKEY_LOCAL_MACHINE\SOFTWARE\Adobe\InDesign\Version. On macOS: Check /Applications/Adobe InDesign/Contents/Info.plistVerify Fix Applied:
Verify version is 21.0.1 or 19.5.6 or later in Help > About InDesign menu.📡 Detection & Monitoring
Log Indicators:
- Unexpected InDesign crashes
- Process creation from InDesign with unusual command lines
- File access to suspicious InDesign files
Network Indicators:
- Outbound connections from InDesign process to unknown IPs
- DNS requests for suspicious domains from InDesign
SIEM Query:
process_name:"InDesign.exe" AND (event_type:process_creation OR event_type:crash)