CVE-2025-36353
📋 TL;DR
This vulnerability in IBM Db2 allows a local user to cause a denial of service by exploiting improper neutralization of special elements in data query logic. It affects Db2 versions 11.5.0-11.5.9 and 12.1.0-12.1.3 on Linux, UNIX, and Windows systems. The attacker must have local access to the database server.
💻 Affected Systems
- IBM Db2 for Linux, UNIX and Windows
- IBM Db2 Connect Server
📦 What is this software?
Db2 by Ibm
Db2 by Ibm
Db2 by Ibm
Db2 by Ibm
Db2 by Ibm
Db2 by Ibm
⚠️ Risk & Real-World Impact
Worst Case
Complete database unavailability affecting all applications and users relying on the Db2 instance, potentially causing extended business disruption.
Likely Case
Temporary service degradation or database crashes requiring restart, impacting application availability until recovery.
If Mitigated
Minimal impact with proper access controls limiting local user privileges and monitoring for suspicious activity.
🎯 Exploit Status
Requires local access and knowledge of database query logic. No public exploit code is currently available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Apply IBM Db2 fixes: 11.5.9.0a or later for 11.5.x, 12.1.3.0a or later for 12.1.x
Vendor Advisory: https://www.ibm.com/support/pages/node/7257632
Restart Required: Yes
Instructions:
1. Download the appropriate fix pack from IBM Fix Central. 2. Stop all Db2 services and applications. 3. Apply the fix pack following IBM installation instructions. 4. Restart Db2 services and verify functionality.
🔧 Temporary Workarounds
Restrict local user access
allLimit local user accounts that can access the Db2 instance to only necessary administrative users.
# Review and remove unnecessary local users from Db2 groups
# Use OS-level access controls to restrict /opt/ibm/db2/ directory
Implement query monitoring
allMonitor and log suspicious query patterns that could trigger the vulnerability.
db2 update dbm cfg using mon_heap_sz 1024
db2 update dbm cfg using mon_req_metrics on
🧯 If You Can't Patch
- Implement strict least-privilege access controls for local users and monitor for unusual database activity.
- Deploy network segmentation to isolate Db2 servers from non-essential systems and users.
🔍 How to Verify
Check if Vulnerable:
Check Db2 version with: db2level | grep 'Product identifier'Check Version:
db2levelVerify Fix Applied:
Verify version is patched: db2level should show 11.5.9.0a or higher, or 12.1.3.0a or higher📡 Detection & Monitoring
Log Indicators:
- Unexpected database crashes or restarts in db2diag.log
- Suspicious query patterns in db2 audit logs
Network Indicators:
- Increased database connection errors from applications
- Unusual local user database activity patterns
SIEM Query:
source="db2diag.log" AND ("crash" OR "abend" OR "terminated unexpectedly")