Critical Vulnerability in Splunk Enterprise for Windows Enables SYSTEM-Level Access via DLL Hijacking
Splunk has recently identified a significant security vulnerability within its Splunk Enterprise software for Windows platforms. This flaw, cataloged as CVE-2026-20140, allows users with minimal privileges to escalate their access rights to SYSTEM level by exploiting a DLL search-order hijacking weakness.
Understanding the Vulnerability
The core of this vulnerability lies in the way Splunk Enterprise handles the loading of Dynamic Link Libraries (DLLs) during its startup process. Specifically, the application searches for required DLLs in a sequence that can be manipulated by an attacker. By strategically placing a malicious DLL in a directory that the application scans before the legitimate library location, an attacker can deceive the application into executing their code. Given that Splunk Enterprise operates with SYSTEM-level privileges, the injected code inherits these elevated rights, granting the attacker full control over the affected system.
Technical Details
– CVE Identifier: CVE-2026-20140
– Severity Rating: High (CVSSv3.1 score of 7.7)
– Common Weakness Enumeration (CWE): CWE-427 (Uncontrolled Search Path Element)
The CVSS vector string for this vulnerability is CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H, indicating:
– Attack Vector (AV): Local – The attacker needs local access to the system.
– Attack Complexity (AC): High – Exploiting this vulnerability requires significant effort and specific conditions.
– Privileges Required (PR): Low – The attacker does not need high-level privileges to exploit the vulnerability.
– User Interaction (UI): Required – Some form of user interaction is necessary for the exploit to succeed.
– Scope (S): Changed – Exploiting the vulnerability can affect resources beyond the immediate scope of the vulnerable component.
– Confidentiality (C), Integrity (I), Availability (A) Impact: High – Successful exploitation can lead to significant breaches in data confidentiality, integrity, and system availability.
Affected Versions
The vulnerability impacts the following versions of Splunk Enterprise for Windows:
– 10.0 Series: Versions 10.0.0 to 10.0.2
– 9.4 Series: Versions 9.4.0 to 9.4.7
– 9.3 Series: Versions 9.3.0 to 9.3.8
– 9.2 Series: Versions 9.2.0 to 9.2.11
It’s important to note that non-Windows deployments of Splunk Enterprise are not affected by this vulnerability.
Mitigation and Remediation
To address this security issue, Splunk has released patches in the following versions:
– 10.0 Series: Version 10.0.3
– 9.4 Series: Version 9.4.8
– 9.3 Series: Version 9.3.9
– 9.2 Series: Version 9.2.12
Organizations utilizing Splunk Enterprise on Windows systems are strongly advised to upgrade to these patched versions promptly to mitigate the risk associated with this vulnerability.
For environments where immediate patching is not feasible, administrators should implement the following interim measures:
1. Restrict Directory Permissions: Ensure that write permissions are limited on directories within the system drive to prevent unauthorized placement of malicious DLLs.
2. Monitor System Directories: Regularly inspect system directories for unauthorized files or changes that could indicate an attempted exploit.
3. User Education: Educate users about the risks of DLL hijacking and the importance of maintaining secure practices, such as not downloading or executing unverified files.
Discovery and Reporting
This vulnerability was responsibly disclosed by security researcher Marius Gabriel Mihai. As of the latest reports, there have been no known instances of this vulnerability being exploited in the wild.
Conclusion
The discovery of CVE-2026-20140 underscores the critical importance of maintaining up-to-date software and implementing robust security measures. Organizations relying on Splunk Enterprise for Windows should prioritize applying the necessary patches and consider additional security practices to safeguard their systems against potential exploits.
