CVE-2025-36353 Overview
A denial of service vulnerability has been identified in IBM Db2 for Linux, UNIX, and Windows (including Db2 Connect Server) affecting versions 11.5.0 through 11.5.9 and 12.1.0 through 12.1.3. The vulnerability stems from improper neutralization of special elements in data query logic (CWE-943), which could allow a local user to disrupt database availability.
Critical Impact
A local attacker with low privileges can exploit this vulnerability to cause a denial of service condition, potentially disrupting critical database operations and affecting business continuity.
Affected Products
- IBM Db2 for Linux versions 11.5.0 - 11.5.9
- IBM Db2 for Linux versions 12.1.0 - 12.1.3
- IBM Db2 for UNIX versions 11.5.0 - 11.5.9
- IBM Db2 for UNIX versions 12.1.0 - 12.1.3
- IBM Db2 for Windows versions 11.5.0 - 11.5.9
- IBM Db2 for Windows versions 12.1.0 - 12.1.3
- IBM Db2 Connect Server (all affected versions above)
Discovery Timeline
- 2026-01-30 - CVE-2025-36353 published to NVD
- 2026-02-05 - Last updated in NVD database
Technical Details for CVE-2025-36353
Vulnerability Analysis
This vulnerability is classified under CWE-943: Improper Neutralization of Special Elements in Data Query Logic. The flaw exists in how IBM Db2 processes and validates special elements within data query logic. When specially crafted input is processed by the database engine, it fails to properly neutralize certain elements, leading to resource exhaustion or service disruption.
The local attack vector requires an attacker to have existing access to the system where Db2 is installed. While no authentication bypass is involved, users with low-level privileges can construct malicious queries that trigger the denial of service condition. The impact is limited to availability—there is no compromise of data confidentiality or integrity.
Root Cause
The root cause lies in insufficient input validation and sanitization mechanisms within the Db2 query processing engine. When data query logic contains specially crafted elements, the system fails to properly handle or neutralize these inputs before processing. This improper handling can lead to unexpected behavior in the query execution path, ultimately causing the database service to become unresponsive or crash.
CWE-943 specifically addresses vulnerabilities where applications construct data queries using user-supplied input without adequate protection against malicious query structures. In this case, the Db2 engine does not adequately validate certain special elements that can be embedded in query logic.
Attack Vector
The attack requires local access to a system running a vulnerable version of IBM Db2. An attacker with low privileges can exploit this vulnerability by:
- Crafting a data query containing malicious special elements
- Submitting the query to the Db2 database engine
- Triggering improper processing that leads to service disruption
The vulnerability does not require user interaction beyond the initial malicious query submission. Due to the local attack vector, exploitation is limited to users who already have some form of access to the database system, reducing the overall exposure compared to remotely exploitable vulnerabilities.
No verified proof-of-concept code is publicly available for this vulnerability. The attack leverages improper handling of special elements in query logic, and organizations should refer to the IBM Security Advisory for specific technical details about the vulnerable components.
Detection Methods for CVE-2025-36353
Indicators of Compromise
- Unexpected Db2 service crashes or restarts without scheduled maintenance
- Database connection timeouts or failures reported by applications
- Unusual query patterns in Db2 diagnostic logs containing special characters or malformed syntax
- Resource exhaustion alerts related to Db2 processes
Detection Strategies
- Monitor Db2 diagnostic logs (db2diag.log) for abnormal termination events and query parsing errors
- Implement database activity monitoring (DAM) to detect unusual query patterns from local users
- Configure alerts for Db2 service availability and automatic restart events
- Review audit logs for queries containing suspicious special elements or escape sequences
Monitoring Recommendations
- Enable comprehensive Db2 audit logging to capture all query activity
- Configure monitoring for Db2 process health and resource utilization
- Set up automated alerting for service availability degradation
- Implement baseline analysis for normal query patterns to detect anomalous activity
How to Mitigate CVE-2025-36353
Immediate Actions Required
- Identify all IBM Db2 installations running versions 11.5.0-11.5.9 or 12.1.0-12.1.3
- Review and restrict local access privileges to Db2 systems
- Apply the security patch from IBM as soon as possible
- Implement additional monitoring for Db2 service availability
- Consider implementing query filtering or validation at the application layer
Patch Information
IBM has released a security update to address this vulnerability. Administrators should apply the appropriate fix pack or interim fix for their Db2 version. Detailed patch information and download links are available from the IBM Support Page.
Organizations should prioritize patching based on the criticality of their Db2 deployments and the exposure of systems to local users. Testing patches in non-production environments before deployment is recommended to ensure compatibility.
Workarounds
- Restrict database access to only essential users with legitimate business needs
- Implement strict principle of least privilege for all local Db2 accounts
- Deploy additional monitoring and logging to detect exploitation attempts
- Consider network segmentation to limit access to Db2 systems
- Review and audit all local user accounts with Db2 access permissions
# Review local users with Db2 access
db2 "SELECT GRANTEE, GRANTEETYPE, DBADMAUTH FROM SYSCAT.DBAUTH WHERE DBADMAUTH = 'Y'"
# Enable comprehensive audit logging
db2audit configure scope all status both
# Monitor Db2 diagnostic logs for anomalies
tail -f /home/db2inst1/sqllib/db2dump/db2diag.log
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
