CVE-2026-21275
📋 TL;DR
Adobe InDesign versions 21.0, 19.5.5 and earlier contain an uninitialized pointer access vulnerability that allows arbitrary code execution when a user opens a malicious file. This affects all users running vulnerable versions of InDesign on their desktop systems.
💻 Affected Systems
- Adobe InDesign
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with attacker gaining the same privileges as the logged-in user, potentially leading to data theft, ransomware deployment, or lateral movement.
Likely Case
Malicious document leads to malware installation or credential theft when opened by a user.
If Mitigated
User opens suspicious file but security controls prevent execution, resulting in application crash only.
🎯 Exploit Status
Exploitation requires user interaction (opening malicious file) and knowledge of memory corruption techniques.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Update to InDesign 21.0.1 or 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 Updates section. 3. Install available InDesign updates. 4. Restart computer after installation completes.
🔧 Temporary Workarounds
Restrict InDesign file execution
allConfigure application control to block execution of InDesign files from untrusted sources
User awareness training
allTrain users to only open InDesign files from trusted sources
🧯 If You Can't Patch
- Implement application whitelisting to prevent unauthorized InDesign execution
- Use email/web gateways to block suspicious InDesign file attachments
🔍 How to Verify
Check if Vulnerable:
Check InDesign version via Help > About InDesign. If version is 21.0, 19.5.5 or earlier, system is vulnerable.Check Version:
On Windows: Check Add/Remove Programs for Adobe InDesign version. On macOS: Check Applications folder > Adobe InDesign > Get Info.Verify Fix Applied:
Verify version is 21.0.1 or 19.5.6 after update installation.📡 Detection & Monitoring
Log Indicators:
- Unexpected InDesign crashes
- InDesign spawning unusual child processes
- InDesign accessing suspicious files
Network Indicators:
- InDesign making unexpected outbound connections after file open
SIEM Query:
process_name:"InDesign.exe" AND (event_type:crash OR parent_process:unusual)