CVE-2025-36387 Overview
CVE-2025-36387 is a Denial of Service (DoS) vulnerability affecting IBM Db2 for Linux, UNIX and Windows (including DB2 Connect Server) versions 11.5.0 through 11.5.9. The vulnerability allows an authenticated user to cause a denial of service condition when submitting a specially crafted query to the database server. This vulnerability is classified under CWE-770 (Allocation of Resources Without Limits or Throttling), indicating that the database engine fails to properly limit resource consumption during query processing.
Critical Impact
Authenticated attackers can disrupt database availability by sending malicious queries, potentially causing service outages for enterprise applications dependent on IBM Db2.
Affected Products
- IBM Db2 for Linux 11.5.0 - 11.5.9
- IBM Db2 for UNIX 11.5.0 - 11.5.9
- IBM Db2 for Windows 11.5.0 - 11.5.9
Discovery Timeline
- 2026-01-30 - CVE CVE-2025-36387 published to NVD
- 2026-02-05 - Last updated in NVD database
Technical Details for CVE-2025-36387
Vulnerability Analysis
This vulnerability stems from improper resource allocation controls within the IBM Db2 query processing engine. When the database receives a specially crafted query from an authenticated user, it fails to enforce appropriate limits on resource consumption, leading to resource exhaustion. The flaw requires network access and low-privilege authentication, making it exploitable by any authenticated database user. The impact is limited to availability—there is no impact to confidentiality or integrity of data.
The vulnerability is particularly concerning in multi-tenant environments or shared database deployments where lower-privileged users could disrupt services for other users and applications.
Root Cause
The root cause is identified as CWE-770: Allocation of Resources Without Limits or Throttling. The Db2 query processor does not adequately constrain resource allocation when handling certain malformed or complex query structures. This allows an attacker to craft queries that consume excessive memory, CPU cycles, or other system resources without proper bounds checking.
Attack Vector
The attack is conducted over the network by an authenticated user submitting specially crafted SQL queries to the Db2 database server. The attacker requires valid database credentials with at least basic query execution privileges. No user interaction is required for exploitation, and the attack can be automated once the malicious query structure is identified.
The attack does not require administrative privileges—any authenticated user with query execution rights can potentially trigger the denial of service condition. This makes the vulnerability accessible to a broad range of potential attackers, including malicious insiders or compromised application service accounts.
Detection Methods for CVE-2025-36387
Indicators of Compromise
- Abnormal spikes in database resource utilization (CPU, memory) without corresponding increase in legitimate workload
- Db2 database instances becoming unresponsive or timing out on routine queries
- Unusual query patterns from specific user accounts, particularly queries with complex or malformed structures
- Database crash logs or error messages indicating resource exhaustion conditions
Detection Strategies
- Monitor Db2 diagnostic logs for resource allocation failures or memory exhaustion errors
- Implement query performance monitoring to detect unusually long-running or resource-intensive queries
- Configure database alerts for abnormal resource consumption patterns
- Review authentication logs for suspicious user activity preceding service disruptions
- Deploy SentinelOne Singularity Platform for real-time behavioral analysis of database server processes
Monitoring Recommendations
- Enable detailed Db2 query logging and audit trails for forensic analysis
- Set up threshold-based alerting for database resource metrics (CPU, memory, connection pool)
- Monitor for repeated failed or abnormal query submissions from the same user account
- Implement baseline monitoring to detect deviations from normal database operation patterns
How to Mitigate CVE-2025-36387
Immediate Actions Required
- Apply the security update from IBM as detailed in the IBM Support Advisory
- Review database user permissions and implement principle of least privilege for query execution
- Implement query timeout limits and resource governor policies where supported
- Monitor database servers for unusual activity while patching is coordinated
Patch Information
IBM has released a security update to address this vulnerability. Organizations running affected versions of IBM Db2 (11.5.0 through 11.5.9) should consult the IBM Support Page for detailed patch information and upgrade instructions.
Workarounds
- Implement strict query resource limits at the database level to prevent resource exhaustion
- Restrict network access to the Db2 server to trusted hosts and subnets only
- Review and minimize the number of accounts with direct query execution privileges
- Consider implementing a database activity monitoring (DAM) solution to detect and block malicious queries
- Segment database servers on isolated network segments with enhanced monitoring
# Example: Configure connection timeout and query resource limits
# Consult IBM documentation for your specific Db2 version
db2 update dbm cfg using QUERY_HEAP_SZ 8000
db2 update dbm cfg using CONN_ELAPSE 60
db2 update db cfg using LOCKTIMEOUT 30
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
