CVE-2025-36186: IBM Db2 Privilege Escalation Vulnerability

CVE-2025-36186 Overview

CVE-2025-36186 is a local privilege escalation vulnerability affecting IBM Db2 12.1.0 through 12.1.3 for Linux, UNIX, and Windows, including Db2 Connect Server. Under specific configurations, a local authenticated user can execute malicious code that escalates privileges to root. The flaw stems from execution of unnecessary privileges operated at a higher-than-minimum level, classified under [CWE-250] (Execution with Unnecessary Privileges).

Critical Impact
A local attacker with low-privileged access can achieve root-level code execution on affected Db2 servers, compromising database confidentiality, integrity, and availability.

Affected Products

IBM Db2 12.1.0 for Linux, UNIX, and Windows
IBM Db2 12.1.1 through 12.1.3 for Linux, UNIX, and Windows
IBM Db2 Connect Server 12.1.0 through 12.1.3

Discovery Timeline

2025-11-07 - CVE-2025-36186 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-36186

Vulnerability Analysis

CVE-2025-36186 affects the Db2 database engine on Linux, UNIX, and Windows platforms. The vulnerability enables a local user with existing low-privilege access on the host to escalate to root. Successful exploitation grants full administrative control over the database server and the underlying operating system.

The attack requires local access and low privileges, with no user interaction. Because Db2 processes handle sensitive workloads and often run in shared enterprise environments, root compromise on the host can cascade to backup systems, replicated databases, and connected application tiers.

Root Cause

The underlying weakness is [CWE-250]: Execution with Unnecessary Privileges. Specific Db2 components execute operations at a privilege level higher than required for their function. When a local user triggers these code paths under vulnerable configurations, the elevated context is inherited by attacker-controlled code, producing root execution.

Attack Vector

Exploitation requires local access to the host running a vulnerable Db2 instance and valid credentials with low privileges. The attacker invokes a Db2 code path that runs with excess privileges, supplying malicious input or a crafted binary that inherits the elevated context. IBM's advisory describes the affected configurations and remediation guidance in the IBM Support Page.

No public proof-of-concept exploit is currently available, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog.

Detection Methods for CVE-2025-36186

Indicators of Compromise

Unexpected root-owned processes spawned by Db2 instance owner accounts or db2sysc child processes.
New setuid binaries, cron entries, or SSH authorized_keys added shortly after Db2 activity by low-privileged users.
Anomalous writes to system directories (/etc, /usr/local/bin) originating from Db2 service accounts.

Detection Strategies

Audit process ancestry for privilege transitions where a Db2 instance user launches a child process running as root.
Monitor Db2 diagnostic logs (db2diag.log) for unusual command executions, extension loads, or error patterns that precede privilege changes.
Correlate local logon events on Db2 hosts with subsequent execution of unusual binaries or shell invocations from database service contexts.

Monitoring Recommendations

Enable Linux auditd rules covering execve, setuid, and setgid syscalls for Db2 service account UIDs.
Track file integrity for Db2 installation directories and system paths writable by the instance owner.
Alert on privilege escalation chains that begin with authenticated Db2 sessions on managed hosts.

How to Mitigate CVE-2025-36186

Immediate Actions Required

Inventory all IBM Db2 12.1.0 through 12.1.3 deployments across Linux, UNIX, and Windows hosts, including Db2 Connect Server installations.
Apply the fix package referenced in the IBM Support Page as soon as change windows permit.
Restrict local shell access on Db2 hosts to a minimal set of administrators and rotate credentials for accounts that had prior local access.

Patch Information

IBM has published remediation guidance for CVE-2025-36186. Administrators should consult the IBM Support Page for the specific fix pack and interim fix versions applicable to Db2 12.1.0 through 12.1.3 and Db2 Connect Server. Apply the vendor-supplied patch to remove the excessive privilege condition in affected code paths.

Workarounds

Limit local access to Db2 servers using operating system access controls, SSH restrictions, and jump-host requirements.
Review Db2 instance configuration against IBM hardening guidance and disable features or extensions not required for production workloads.
Segment Db2 hosts on the network so that a root compromise does not expose backup servers, replication targets, or management planes.

bash

# Verify installed Db2 version on Linux/UNIX hosts
db2level

# List Db2 instances present on the host
/opt/ibm/db2/V12.1/instance/db2ilist

# Review recent diagnostic entries for suspicious activity
tail -n 500 ~/sqllib/db2dump/db2diag.log