CVE-2026-21278
📋 TL;DR
Adobe InDesign versions 21.0, 19.5.5 and earlier contain an out-of-bounds read vulnerability that could allow attackers to access sensitive information from memory. Users who open malicious InDesign files are affected, potentially exposing confidential data stored in application memory.
💻 Affected Systems
- Adobe InDesign Desktop
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attacker gains access to sensitive information like passwords, encryption keys, or proprietary data stored in InDesign's memory space
Likely Case
Information disclosure of application data or system memory contents, potentially including user data or system information
If Mitigated
Limited impact with proper file handling policies and user awareness training
🎯 Exploit Status
Requires user interaction (opening malicious file) and knowledge of memory layout
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Update to version 21.0.1 or later, or 19.5.6 or later
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 InDesign and click 'Update' 4. Restart computer after installation completes
🔧 Temporary Workarounds
Restrict file opening
allConfigure application control policies to restrict opening of InDesign files from untrusted sources
User awareness training
allTrain users to only open InDesign files from trusted sources and verify file integrity
🧯 If You Can't Patch
- Implement application whitelisting to block execution of vulnerable InDesign versions
- Deploy email filtering and web gateways to block malicious InDesign file attachments
🔍 How to Verify
Check if Vulnerable:
Check InDesign version via Help > About InDesign menuCheck Version:
On Windows: wmic product where name="Adobe InDesign" get version
On macOS: /Applications/Adobe\ InDesign\ */Adobe\ InDesign.app/Contents/MacOS/Adobe\ InDesign -vVerify Fix Applied:
Verify version is 21.0.1 or later, or 19.5.6 or later📡 Detection & Monitoring
Log Indicators:
- Application crashes with memory access violations
- Unexpected file opening events in InDesign
Network Indicators:
- Inbound malicious file transfers via email or web
SIEM Query:
source="*indesign*" AND (event_type="crash" OR event_type="file_open") AND file_extension="indd"