CVE-2025-36009 Overview
IBM Db2 for Linux, UNIX and Windows (includes DB2 Connect Server) contains a denial of service vulnerability that allows an authenticated user to disrupt database availability through excessive use of a global variable. This vulnerability falls under CWE-1284 (Improper Validation of Specified Quantity in Input), indicating the database engine fails to properly validate or limit the usage of certain global variables.
Critical Impact
Authenticated attackers can cause denial of service conditions affecting database availability, potentially disrupting business-critical applications and services that depend on IBM Db2 databases.
Affected Products
- IBM Db2 for Linux
- IBM Db2 for UNIX
- IBM Db2 for Windows (includes DB2 Connect Server)
Discovery Timeline
- 2026-01-30 - CVE CVE-2025-36009 published to NVD
- 2026-02-04 - Last updated in NVD database
Technical Details for CVE-2025-36009
Vulnerability Analysis
This vulnerability enables authenticated users to cause a denial of service condition in IBM Db2 database instances. The flaw stems from improper handling of global variables within the database engine, where excessive manipulation of these variables can lead to resource exhaustion or system instability.
The attack requires network access and valid authentication credentials, meaning the attacker must have legitimate access to the database system. However, once authenticated, low-privilege users can exploit this vulnerability without requiring administrative permissions or user interaction.
The primary impact is on system availability, with no direct effect on data confidentiality or integrity. Organizations relying on IBM Db2 for critical operations should treat this as a significant availability risk.
Root Cause
The root cause is categorized under CWE-1284 (Improper Validation of Specified Quantity in Input). The database engine does not adequately validate or enforce limits on the usage of global variables, allowing authenticated users to consume excessive resources through repeated or malicious variable operations. This lack of proper bounds checking enables the denial of service condition.
Attack Vector
The attack vector is network-based, requiring an authenticated session to the IBM Db2 database. An attacker with valid credentials can exploit this vulnerability by sending specially crafted requests that cause excessive use of global variables within the database system.
The attack sequence involves:
- Establishing an authenticated connection to the target IBM Db2 instance
- Executing operations that manipulate global variables beyond normal operational bounds
- Exhausting system resources through repeated or amplified variable usage
- Causing the database to become unresponsive or unavailable to legitimate users
No proof-of-concept exploits have been publicly released, and this vulnerability is not currently listed on CISA's Known Exploited Vulnerabilities catalog.
Detection Methods for CVE-2025-36009
Indicators of Compromise
- Unusual spikes in database resource consumption (CPU, memory) without corresponding legitimate workload increases
- Multiple failed or slow database connections reported by application servers
- Database logs showing abnormal global variable access patterns or resource limit warnings
- Authenticated sessions performing repetitive operations outside normal usage baselines
Detection Strategies
- Implement database activity monitoring to track global variable operations and establish usage baselines
- Configure alerts for resource consumption anomalies in IBM Db2 instances
- Monitor authentication logs for accounts performing unusual numbers of database operations
- Deploy SentinelOne Singularity XDR to correlate database server behavior with endpoint telemetry for comprehensive threat detection
Monitoring Recommendations
- Enable detailed IBM Db2 audit logging to capture variable access patterns and session activities
- Establish baseline metrics for normal database resource usage and configure threshold-based alerting
- Implement real-time monitoring of database server health metrics including memory utilization and connection pool status
- Review database administrative and diagnostic logs regularly for signs of exploitation attempts
How to Mitigate CVE-2025-36009
Immediate Actions Required
- Review and apply the latest IBM security patches for Db2 installations as documented in the IBM support advisory
- Audit database user accounts and revoke unnecessary privileges to limit potential attack surface
- Implement network segmentation to restrict database access to authorized application servers only
- Enable enhanced monitoring on Db2 instances to detect potential exploitation attempts
Patch Information
IBM has released security updates to address this vulnerability. Detailed patch information and remediation guidance is available through the IBM Support Documentation. Organizations should prioritize patching based on the criticality of their Db2 deployments and exposure to authenticated users.
Verify your current IBM Db2 version using:
db2level
Compare the output against the vulnerable versions listed in the IBM security bulletin to determine if patching is required.
Workarounds
- Implement strict database connection limits and session timeout policies to reduce exploitation windows
- Configure resource governors within Db2 to limit per-session resource consumption where supported
- Apply principle of least privilege by restricting database access to only essential accounts and services
- Consider implementing database proxy solutions that can filter and monitor incoming queries for suspicious patterns
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
