CVE-2026-104364 Overview
CVE-2026-104364 is an improper input validation vulnerability [CWE-20] in IBM Db2 that allows an authenticated local attacker to trigger a denial of service condition. The flaw affects IBM Db2 versions 11.5.0 through 11.5.9 and 12.1.0 through 12.1.5. Exploitation requires local access and low-level privileges on the database host. Successful exploitation impacts availability of the database service without exposing data confidentiality or allowing arbitrary modification. IBM has published remediation guidance on its support portal.
Critical Impact
A low-privileged local user can disrupt availability of IBM Db2 database services through crafted input that bypasses validation routines.
Affected Products
- IBM Db2 11.5.0 through 11.5.9
- IBM Db2 12.1.0 through 12.1.5
- Deployments running affected Db2 versions on supported operating systems
Discovery Timeline
- 2026-10-12 - CVE-2026-104364 published to the National Vulnerability Database
- 2026-10-13 - Last updated in NVD database
Technical Details for CVE-2026-104364
Vulnerability Analysis
The vulnerability resides in input validation logic within IBM Db2. An authenticated local attacker can submit malformed or unexpected input that the database engine fails to validate correctly. The result is a denial of service condition against the Db2 service. The issue affects both the 11.5.x and 12.1.x branches, indicating a shared code path across major releases.
The attack vector is local, meaning the attacker must have an existing session or shell on the host running Db2. No user interaction is required beyond submitting the malformed input. The scope of impact is limited to availability, with no direct path to data exfiltration or arbitrary code execution reported in the advisory.
The EPSS probability indicates a low likelihood of exploitation activity in the short term, consistent with the local attack prerequisite.
Root Cause
The root cause is classified under [CWE-20] Improper Input Validation. Db2 does not adequately verify properties of input values before using them in processing. Crafted input triggers an unhandled condition that disrupts the service. IBM has not published the specific vulnerable component in the public advisory text.
Attack Vector
An attacker with local access and low privileges on a system running an affected Db2 version submits malformed input through a supported Db2 interface. The engine fails to validate the input and enters a condition that terminates or hangs service availability. See the IBM Support Page for Node 7291615 for vendor technical details.
Detection Methods for CVE-2026-104364
Indicators of Compromise
- Unexpected termination or restarts of the db2sysc process on affected hosts
- Db2 diagnostic log (db2diag.log) entries showing input validation errors or abrupt shutdowns
- Repeated failed queries or malformed input patterns originating from local user sessions
Detection Strategies
- Monitor Db2 service availability metrics for unexplained outages correlated with local user activity
- Review Db2 audit facility (db2audit) logs for anomalous command patterns from low-privileged accounts
- Correlate operating system logs with Db2 service restarts to identify the originating user session
Monitoring Recommendations
- Enable Db2 audit logging for all local sessions on database servers
- Alert on repeated db2sysc crashes or service restarts within short time windows
- Track local privilege use on database hosts to identify untrusted accounts with Db2 access
How to Mitigate CVE-2026-104364
Immediate Actions Required
- Review the IBM Support Page for Node 7291615 and apply the fix pack or interim fix for your Db2 release
- Inventory all Db2 instances to identify systems running versions 11.5.0 through 11.5.9 or 12.1.0 through 12.1.5
- Restrict local shell and database access on Db2 hosts to trusted administrators only
Patch Information
IBM has published remediation details on its support portal. Administrators should apply the vendor-supplied fix pack or interim fix referenced in the IBM Support Page for Node 7291615. Confirm the fix level after upgrade using db2level.
Workarounds
- Limit local login access to Db2 database servers to a minimal set of administrative accounts
- Enforce least privilege for database users and remove unnecessary local accounts
- Monitor and rate-limit abnormal query patterns from local sessions until the patch is deployed
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
