CVE-2026-76255: Splunk Enterprise Auth Bypass Vulnerability

CVE-2026-76255 Overview

CVE-2026-76255 is a missing authorization vulnerability [CWE-862] in Splunk Enterprise. The flaw affects versions below 10.4.1, 10.2.6, 10.0.8, and 9.4.13. A low-privileged user who does not hold the admin or power roles can trick a higher-privileged user into executing arbitrary Search Processing Language (SPL) commands. The attack occurs through the Data Model Editor, which fails to apply SPL safeguards for risky commands when running the base search for auto-extracted fields. Successful exploitation lets an attacker access data and impact system integrity using the victim's permissions.

Critical Impact
Attackers can execute arbitrary SPL commands with the victim's privileges, exposing data and compromising Splunk system integrity through Data Model Editor requests.

Affected Products

Splunk Enterprise versions below 10.4.1
Splunk Enterprise versions below 10.2.6 and 10.0.8
Splunk Enterprise versions below 9.4.13

Discovery Timeline

2026-08-19 - CVE-2026-76255 published to NVD
2026-08-20 - Last updated in NVD database

Technical Details for CVE-2026-76255

Vulnerability Analysis

The vulnerability resides in the Splunk Web Data Model Editor component. Splunk enforces SPL safeguards for risky commands to block untrusted execution paths. The Data Model Editor bypasses these safeguards when it runs the base search for auto-extracted fields. An attacker with a low-privileged Splunk account crafts a malicious request that triggers this base search. If a higher-privileged user follows a phishing link, their browser initiates the request under their session. The commands then execute with the victim's role, granting access to all data available to that user. Exploitation is not fully attacker-controlled because it requires user interaction, but the impact aligns with confidentiality and integrity compromise.

Root Cause

The root cause is a missing authorization check [CWE-862] in the Data Model Editor code path. Splunk Web does not evaluate SPL safeguards for risky commands during auto-extracted field base searches. The editor treats the base search as an internal operation rather than a user-issued query subject to safeguard policy.

Attack Vector

The attack vector is network-based and requires user interaction. An attacker with a valid but low-privileged Splunk account crafts a URL or web request that targets the Data Model Editor. The attacker phishes an admin or power user into loading the request in an authenticated browser session. The victim's browser submits the request, and the server executes the embedded SPL under the victim's role. The vulnerability does not allow direct exploitation at will by the low-privileged attacker.

No verified proof-of-concept code is publicly available. Refer to the Splunk Security Advisory SVD-2026-0801 for vendor technical details.

Detection Methods for CVE-2026-76255

Indicators of Compromise

Unexpected Data Model Editor requests originating from user sessions that do not typically build data models.
Splunk audit log entries showing risky SPL commands executed by admin or power users shortly after clicking external links.
HTTP referrers on Splunk Web requests pointing to untrusted external domains.

Detection Strategies

Monitor Splunk internal _audit and _internal indexes for unusual datamodel REST endpoint activity tied to privileged users.
Alert on SPL commands from the risky command list (for example delete, outputlookup, script, run) invoked through the Data Model Editor context.
Correlate web proxy telemetry with Splunk session activity to identify phishing-driven navigations preceding sensitive queries.

Monitoring Recommendations

Enable detailed Splunk Web access logging and forward logs to a centralized analytics platform.
Baseline normal Data Model Editor usage per role and alert on deviations by privileged accounts.
Track user-agent and source-IP anomalies for authenticated sessions of admin and power role holders.

How to Mitigate CVE-2026-76255

Immediate Actions Required

Upgrade Splunk Enterprise to 10.4.1, 10.2.6, 10.0.8, 9.4.13, or later as documented by the vendor.
Restrict membership in the admin and power roles to reduce the population of phishing targets.
Communicate phishing awareness guidance to Splunk administrators, focusing on links that load Splunk Web endpoints.

Patch Information

Splunk has released fixed versions in the 10.4.1, 10.2.6, 10.0.8, and 9.4.13 release lines. Review the Splunk Security Advisory SVD-2026-0801 for full remediation guidance and version mapping.

Workarounds

Review and enforce SPL safeguards for risky commands across all roles, following Splunk's best-practice documentation.
Limit the edit_datamodel capability to trusted roles only and audit capability assignments regularly.
Require re-authentication or session isolation for privileged users when accessing Splunk Web from shared browsers.

bash

# Example: audit which roles hold data model editing capability
# Run in Splunk search to enumerate roles with edit_datamodel capability
| rest /services/authorization/roles \
| search capabilities=edit_datamodel \
| table title capabilities imported_capabilities