Splunk RCE via `/splunkd/__upload/indexing/preview` and `unarchive_cmd` (CVE-2026-20163)
Splunk disclosed a high-severity remote command execution (RCE) vulnerability, CVE-2026-20163 (CVSS 8.0), affecting Splunk Enterprise and Splunk Cloud Platform. The issue is a command injection weakness (CWE-77) in the REST endpoint /splunkd/__upload/indexing/preview, where user-controlled input is insufficiently sanitized during the “uploaded file preview before indexing” workflow.
Exploitation requires an authenticated user whose role includes the high-privilege capability edit_cmd; under that condition, an attacker can abuse the unarchive_cmd parameter to execute arbitrary shell commands on the underlying host. Reported affected versions include Splunk Enterprise 10.0.0–10.0.3, 9.4.0–9.4.8, and 9.3.0–9.3.9, plus Splunk Cloud Platform versions below 10.2.2510.5, 10.1.2507.16, 10.0.2503.12, and 9.3.2411.124; fixed thresholds are Enterprise 10.0.4, 9.4.9, 9.3.10, and 10.2.0 (with the base Enterprise 10.2 release noted as not affected). The disclosure credits researcher Danylo Dmytriiev (DDV_UA) along with Splunk personnel Gabriel Nitu and James Ervin.
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How this story unfolded
2 events from the most recent confirmed update back to the earliest known activity.
Splunk releases fixes and begins cloud patch deployment
Splunk made fixed versions available for affected Splunk Enterprise and Splunk Cloud Platform releases and stated it was deploying patches to impacted cloud instances. The company also recommended upgrading immediately or removing the edit_cmd capability from roles as a workaround.
Splunk discloses CVE-2026-20163 command injection vulnerability
Splunk disclosed a high-severity vulnerability, CVE-2026-20163, affecting Splunk Enterprise and Splunk Cloud Platform. The flaw allows authenticated users with the edit_cmd capability to execute arbitrary shell commands via the /splunkd/__upload/indexing/preview REST endpoint using the unarchive_cmd parameter.
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Splunk RCE Vulnerability Allows Attackers to Execute Arbitrary Shell Commands
cybersecuritynews.com
Open sourceCVE-2026-20163 - Remote Command Execution (RCE) through the '/splunkd/__upload/indexing/preview' REST endpoint in Splunk Enterprise
cvefeed.io
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Splunk has disclosed six critical security vulnerabilities affecting both Splunk Enterprise and Splunk Cloud Platform, exposing organizations to significant risks. The vulnerabilities include multiple cross-site scripting (XSS) flaws, an unauthenticated server-side request forgery (SSRF) vulnerability, and other weaknesses in Splunk’s web components. Two of the most notable XSS vulnerabilities are CVE-2025-20367, a reflected XSS in the /app/search/table endpoint, and CVE-2025-20368, a stored XSS in the Saved Search and Job Inspector features. Both XSS flaws can be exploited by low-privileged users to execute malicious JavaScript in the browsers of other users, potentially compromising user sessions and exposing sensitive data. The SSRF vulnerability, CVE-2025-20371, is particularly severe as it allows unauthenticated attackers to coerce Splunk into making REST API calls on behalf of authenticated high-privilege users, which could lead to further compromise of internal systems. These vulnerabilities affect multiple versions of Splunk Enterprise, specifically those below 10.0.1, 9.4.4, 9.3.6, and 9.2.8, as well as various versions of Splunk Cloud Platform. Successful exploitation of these flaws could allow attackers to gain unauthorized access, escalate privileges, and perform actions on behalf of legitimate users. Splunk has released patches addressing all six vulnerabilities and urges administrators to update their deployments immediately to mitigate the risks. The vulnerabilities highlight the importance of regular security assessments and prompt patch management in enterprise environments. Organizations using affected Splunk versions are advised to review their access logs for signs of exploitation and to apply the security updates without delay. The disclosure underscores the potential impact of web-based vulnerabilities in widely used security and analytics platforms. Security teams should also consider reviewing user permissions and monitoring for unusual activity in Splunk environments. The coordinated disclosure and rapid patching demonstrate the ongoing efforts by vendors and the security community to address critical flaws. These vulnerabilities, if left unpatched, could be leveraged in targeted attacks against organizations relying on Splunk for security monitoring and data analytics. The incident serves as a reminder of the evolving threat landscape and the need for vigilance in securing enterprise software. Splunk’s response includes detailed advisories and guidance for affected customers. The company has not reported any active exploitation in the wild at the time of disclosure, but the technical details provided could accelerate attempts by threat actors to develop exploits. Organizations are encouraged to stay informed about security advisories and to implement layered defenses to reduce the risk of compromise.
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