CVE-2026-105465: IBM Db2 Privilege Escalation Vulnerability

CVE-2026-105465 Overview

CVE-2026-105465 is a privilege escalation vulnerability affecting IBM Db2 versions 11.5.0 through 11.5.9 and 12.1.0 through 12.1.5. The flaw exists when db2locssh is enabled with a Db2 instance, allowing a local authenticated user to elevate privileges. The weakness is categorized under [CWE-269: Improper Privilege Management]. Successful exploitation can impact confidentiality, integrity, and availability of the database environment, and the scope changes to affect resources beyond the vulnerable component.

Critical Impact
A local authenticated attacker can escalate privileges on affected IBM Db2 instances where db2locssh is enabled, gaining control over database operations and potentially the underlying host context.

Affected Products

IBM Db2 11.5.0 through 11.5.9
IBM Db2 12.1.0 through 12.1.5
Deployments where db2locssh is enabled with the Db2 instance

Discovery Timeline

2026-10-12 - CVE-2026-105465 published to NVD
2026-10-13 - Last updated in NVD database

Technical Details for CVE-2026-105465

Vulnerability Analysis

The vulnerability resides in the db2locssh component used by IBM Db2 instances for local SSH-style operations. When enabled, the component mismanages privilege boundaries between the invoking user and the Db2 instance owner. A local authenticated user can leverage this condition to execute operations with privileges exceeding their assigned role.

Because the vulnerability causes a scope change, exploitation affects components beyond the Db2 process itself. This elevates the operational blast radius to the host account context running the Db2 instance. Attackers who already hold low-privileged shell or database access on the server become the primary exploitation path.

IBM Db2 is widely deployed for enterprise data workloads, which makes any post-authentication privilege escalation attractive to adversaries who have already established a foothold. The vulnerability does not require user interaction and can be triggered through local access channels.

Root Cause

The root cause is improper privilege management ([CWE-269]) in the db2locssh helper used by Db2 instances. The helper fails to enforce the expected privilege separation between the calling user and the Db2 instance owner. When db2locssh is enabled, operations invoked through it can run with the instance owner's authority rather than the caller's.

Attack Vector

Exploitation requires local access and valid credentials on the host running an affected IBM Db2 instance. The attacker invokes functionality tied to db2locssh to perform actions in the Db2 instance owner context. No user interaction is required, and attack complexity is low once prerequisites are met. Refer to the IBM Support Page for authoritative technical detail.

No verified public proof-of-concept code is available at the time of writing. The vulnerability mechanism should be understood from the vendor advisory rather than synthetic exploitation examples.

Detection Methods for CVE-2026-105465

Indicators of Compromise

Unexpected invocations of db2locssh by non-instance-owner accounts on Db2 hosts
Db2 instance owner processes spawned from shells belonging to lower-privileged users
New or modified files in Db2 instance directories owned by the instance account but created shortly after low-privileged user activity
Audit log entries showing privileged Db2 operations executed outside of expected administrative sessions

Detection Strategies

Enumerate systems running IBM Db2 11.5.0–11.5.9 and 12.1.0–12.1.5 and determine whether db2locssh is enabled per instance
Correlate operating system process ancestry with Db2 audit records to identify privilege boundary crossings
Alert on execution of db2locssh or related binaries by users who are not the Db2 instance owner or an authorized DBA

Monitoring Recommendations

Enable Db2 audit logging (db2audit) for EXECUTE, SECMAINT, and SYSADMIN categories and forward to a central log store
Monitor Linux and UNIX host telemetry for setuid transitions involving Db2 instance accounts
Track configuration changes to Db2 instance registry variables that control db2locssh activation

How to Mitigate CVE-2026-105465

Immediate Actions Required

Inventory all IBM Db2 instances and identify versions in the affected ranges
Apply the IBM-provided fix referenced on the IBM Support Page as soon as it is validated in a test environment
Restrict local login access to Db2 hosts to administrative personnel only until patching is complete
Review and reduce membership of groups that have shell access on Db2 servers

Patch Information

IBM has published remediation guidance on the IBM Support Page for CVE-2026-105465. Administrators should consult this advisory for the fix pack level that corresponds to their deployed version in the 11.5.x or 12.1.x branches and follow IBM's documented upgrade procedure.

Workarounds

Disable db2locssh on affected Db2 instances where it is not operationally required
Enforce the principle of least privilege for operating system accounts on Db2 hosts
Separate database administrators from general interactive users on the host operating system
Apply host-based access controls that prevent non-authorized users from invoking Db2 helper binaries

bash

# Example: review whether db2locssh is enabled for an instance and inspect ownership
# Run as the Db2 instance owner
db2 get dbm cfg | grep -i ssh
ls -l $(which db2locssh)

# If not required, follow IBM guidance to disable db2locssh for the instance
# and verify no automation depends on it before applying the change.