CVE-2026-76266 in Splunk
Summary
by MITRE • 10/07/2026
In Splunk Enterprise versions below 10.4.3, 10.2.7, 10.0.10, and 9.4.15 on Linux, a local user who can run commands as the user account running Splunk Enterprise could cause an affected Linux package upgrade to run attacker-controlled operating-system commands with root privileges. The vulnerability is possible because the Linux package maintainer script trusts existing Splunk Enterprise installation content when it performs upgrade operations with root privileges. The vulnerability requires an affected Linux package upgrade to occur after the local user modifies the installation. The local user should not be able to elevate privileges at will.
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Analysis
by VulDB Data Team • 10/07/2026
The identified vulnerability in Splunk Enterprise versions prior to 10.4.3, 10.2.7, 10.0.10, and 9.4.15 on Linux systems represents a critical privilege escalation flaw rooted in the software installation lifecycle management mechanisms. This issue specifically affects environments where local users possess the ability to execute commands under the user account responsible for running Splunk Enterprise services. The core technical deficiency lies within the package maintainer scripts utilized during upgrade operations, which exhibit an insecure trust relationship with existing installation content. When a system administrator or automated process initiates a package update, these scripts interact directly with files and directories already present in the Splunk installation directory without sufficiently validating their integrity or origin. This lack of rigorous verification allows any local user operating under the Splunk service account to manipulate specific configuration files or scripts within that directory structure prior to the upgrade event.
The operational impact of this flaw is severe, as it enables an attacker with relatively low-level access to achieve full root privileges on the affected Linux host. By modifying targeted installation artifacts before triggering a package update, the local user can inject malicious commands into the execution flow of the maintainer scripts. Since these scripts execute with elevated permissions to manage system-wide configurations and service states, any injected code is subsequently run as the root user. This effectively bypasses standard access controls and allows for complete compromise of the underlying operating system. The vulnerability highlights a significant gap in defense-in-depth strategies, where reliance on file ownership or directory permissions alone proves insufficient against an insider threat or a compromised low-privilege account that has write access to application-specific directories.
From a classification perspective, this vulnerability aligns with CWE-436, which denotes interpretation ambiguity, and more specifically CWE-94, the improper control of generation of code command injection. The attack vector is consistent with ATT&CK technique T1059, Command and Scripting Interpreter, particularly when leveraged through local file manipulation to achieve privilege escalation via system service management processes like those found in RPM or DEB package managers. The scenario underscores the risks associated with trusting unvalidated input from application-level directories during privileged administrative tasks, a pattern often seen in legacy software deployment mechanisms that prioritize ease of upgrade over strict security boundaries between user-space and root-space operations.
Mitigation strategies must focus on both immediate remediation and long-term architectural improvements. The primary defense is to apply the vendor-provided patches immediately by upgrading Splunk Enterprise to version 10.4.3, 10.2.7, 10.0.10, or 9.4.15, depending on the current deployment branch. These updates include fixes that enforce stricter validation of files during package maintenance operations, ensuring that only expected and verified content is processed with elevated privileges. In addition to patching, organizations should review their Linux package management configurations to ensure that application directories are not writable by non-root users unless absolutely necessary for specific operational requirements. Implementing file integrity monitoring solutions can also help detect unauthorized modifications to critical Splunk files before they trigger a vulnerable upgrade process. Furthermore, adopting principle of least privilege principles across all service accounts is essential; the user account running Splunk should have minimal permissions restricted strictly to runtime needs, thereby reducing the attack surface available for pre-upgrade manipulation.