Critical Vulnerability in Splunk Enterprise for Windows Allows SYSTEM-Level Access via DLL Hijacking
Splunk has recently disclosed a high-severity vulnerability in its Enterprise software for Windows, identified as CVE-2026-20140. This flaw enables low-privileged local users to escalate their privileges to SYSTEM level through a DLL search-order hijacking attack. The vulnerability affects Splunk Enterprise for Windows versions below 10.2.0, 10.0.3, 9.4.8, 9.3.9, and 9.2.12.
Understanding the Vulnerability
The core issue lies in the way Splunk Enterprise handles the loading of dynamic-link libraries (DLLs). An attacker with low-level access can create a directory on the system drive where Splunk is installed and place a malicious DLL within it. Upon restarting the Splunk Enterprise service, the application may inadvertently load this rogue DLL due to an insecure library search order. Since the service operates with SYSTEM-level privileges, the injected code inherits these elevated rights, granting the attacker full control over the host machine.
Technical Details
– CVE Identifier: CVE-2026-20140
– Severity: High (CVSSv3.1 score of 7.7)
– CWE Classification: CWE-427 (Uncontrolled Search Path Element)
– Affected Versions: Splunk Enterprise for Windows versions below 10.2.0, 10.0.3, 9.4.8, 9.3.9, and 9.2.12
Potential Impact
Exploitation of this vulnerability can lead to:
– Complete System Compromise: Attackers can gain full control over the affected system, allowing them to execute arbitrary code, install programs, and modify or delete data.
– Data Breach: Unauthorized access to sensitive information stored on the compromised system.
– Lateral Movement: Attackers may use the compromised system as a foothold to infiltrate other systems within the network.
Mitigation and Remediation
Splunk has addressed this vulnerability in the following versions:
– Splunk Enterprise 10.2.0
– Splunk Enterprise 10.0.3
– Splunk Enterprise 9.4.8
– Splunk Enterprise 9.3.9
– Splunk Enterprise 9.2.12
Organizations running affected versions are strongly urged to upgrade to the appropriate patched version immediately.
Workaround
If immediate patching is not feasible, administrators should:
– Restrict Write Permissions: Limit write access on directories within the system drive to prevent unauthorized DLL placement.
– Monitor System Directories: Regularly check for unauthorized files or directories that could indicate an attempted exploit.
Detection and Reporting
As of now, there have been no reports of active exploitation of this vulnerability in the wild. The issue was responsibly disclosed by security researcher Marius Gabriel Mihai.
Conclusion
This vulnerability underscores the importance of maintaining up-to-date software and implementing strict access controls. Organizations should prioritize patching affected systems and consider additional security measures to mitigate the risk of exploitation.
