CVE-2026-105464: IBM Db2 Privilege Escalation Vulnerability

CVE-2026-105464 Overview

CVE-2026-105464 is a local privilege escalation vulnerability in IBM Db2 for Linux, UNIX and Windows (LUW), including DB2 Connect Server. The flaw stems from improper privilege management [CWE-269] and affects Db2 versions 11.5.0 through 11.5.9 and 12.1.0 through 12.1.5. A local authenticated attacker can abuse the weakness to gain elevated privileges on the database host. Successful exploitation results in a scope change that impacts the confidentiality, integrity, and availability of the system beyond the Db2 process boundary.

Critical Impact
An authenticated local user can escalate to elevated privileges on hosts running affected IBM Db2 LUW or DB2 Connect Server builds, compromising database and host-level security controls.

Affected Products

IBM Db2 for Linux, UNIX and Windows 11.5.0 through 11.5.9
IBM Db2 for Linux, UNIX and Windows 12.1.0 through 12.1.5
IBM DB2 Connect Server (bundled with the affected Db2 LUW releases)

Discovery Timeline

2026-10-12 - CVE-2026-105464 published to NVD
2026-10-13 - Last updated in NVD database

Technical Details for CVE-2026-105464

Vulnerability Analysis

The vulnerability is classified under CWE-269: Improper Privilege Management. IBM Db2 fails to correctly assign, track, or enforce privileges associated with a local user context. An attacker with existing low-privileged access to the host can leverage this weakness to perform actions reserved for higher-privileged accounts. Because the scope is changed, the impact crosses the trust boundary of the Db2 instance owner and can reach the underlying operating system. The attack requires only low-complexity local access with low privileges and no user interaction.

Root Cause

IBM has described the defect as improper privilege management within Db2 LUW. The database engine or an associated binary does not enforce the intended privilege separation between the invoking user and higher-privileged Db2 service accounts. This allows actions executed by a less-privileged user to be processed with the privileges of the Db2 instance owner or root-equivalent accounts. The specific component path has not been publicly detailed by IBM at the time of writing.

Attack Vector

Exploitation requires local, authenticated access to a host running an affected Db2 LUW build. The attacker interacts with Db2 binaries, services, or utilities that mishandle privilege assignment. Remote exploitation over the network is not described in the advisory. Operators should treat any shared database tier, jump host, or multi-tenant Linux system running vulnerable Db2 builds as a priority remediation target.

No verified public proof-of-concept code is available. See the IBM Support Document for vendor-provided technical details.

Detection Methods for CVE-2026-105464

Indicators of Compromise

Unexpected processes spawned by the Db2 instance owner (for example db2inst1) running shells, package managers, or privilege-management utilities.
New or modified SUID/SGID binaries in Db2 installation directories such as /opt/ibm/db2/ or sqllib/.
Audit log gaps or unexplained privilege grants in db2audit output, SYSADM/SYSCTRL role assignments, or OS-level sudoers changes.

Detection Strategies

Inventory Db2 LUW and DB2 Connect Server builds and flag any host running 11.5.0–11.5.9 or 12.1.0–12.1.5.
Enable db2audit with the EXECUTE, SECMAINT, and SYSADMIN categories to capture privilege changes and administrative command invocations.
Correlate OS process creation telemetry with Db2 service accounts to detect lateral movement from database users to the host.

Monitoring Recommendations

Alert on Db2 instance-owner accounts invoking interactive shells, sudo, su, or user-management binaries.
Monitor filesystem integrity on Db2 install paths and watch for new setuid files or unexpected ownership changes.
Forward Db2 audit logs and Linux auditd events to a centralized analytics platform for correlation with authentication events.

How to Mitigate CVE-2026-105464

Immediate Actions Required

Apply the fixed Db2 LUW build identified in the IBM Support Document as soon as change windows allow.
Restrict interactive and SSH access on Db2 hosts to a minimal set of administrators pending patch deployment.
Audit membership of Db2 authorization groups (SYSADM, SYSCTRL, SYSMAINT) and remove unneeded local accounts from the database host.

Patch Information

IBM has published remediation guidance in the IBM Support Document for CVE-2026-105464. Administrators should upgrade affected Db2 LUW instances beyond the vulnerable 11.5.x and 12.1.x ranges to the fix pack identified by IBM. DB2 Connect Server installations bundled with vulnerable Db2 builds require the same remediation.

Workarounds

Enforce least privilege for all local accounts on database hosts and remove shell access for service users where feasible.
Harden file permissions on the Db2 installation directory and verify that no non-administrative users can modify Db2 binaries or configuration files.
Isolate database servers from general-purpose multi-user systems to reduce the pool of potential local attackers.

bash

# Verify installed Db2 level to confirm exposure
db2level

# Review Db2 authorization group members
db2 "SELECT GRANTEE, GRANTEETYPE, DBADMAUTH, SECADMAUTH FROM SYSCAT.DBAUTH"

# Enable auditing of privilege changes and admin actions
db2audit configure scope sysadmin status both
db2audit configure scope secmaint status both
db2audit start