CVE-2026-76309: Splunk Enterprise SQL Injection Vulnerability

CVE-2026-76309 Overview

CVE-2026-76309 is a Structured Query Language (SQL) injection vulnerability [CWE-89] in Splunk Enterprise. The flaw exists in the Representational State Transfer (REST) API, which incorporates user-supplied filter values into database queries without proper neutralization. A low-privileged authenticated user who does not hold the admin or power Splunk role can inject SQL that Splunk Enterprise evaluates as part of a backend database query. Affected versions include Splunk Enterprise below 10.4.2, 10.2.6, 10.0.9, and 9.4.14.

Critical Impact
Authenticated low-privileged users can inject SQL through the REST API filter parameters, causing Splunk Enterprise to evaluate attacker-controlled text within a database query context.

Affected Products

Splunk Enterprise versions below 10.4.2
Splunk Enterprise versions below 10.2.6 and 10.0.9
Splunk Enterprise versions below 9.4.14

Discovery Timeline

2026-08-19 - CVE-2026-76309 published to the National Vulnerability Database (NVD)
2026-08-20 - Last updated in NVD database

Technical Details for CVE-2026-76309

Vulnerability Analysis

The vulnerability resides in Splunk Enterprise's REST API layer, which accepts filter parameters from authenticated clients and passes them into backend database queries. The API does not neutralize special SQL characters or metacharacters before incorporating the filter values into the query string. As a result, attacker-controlled text is parsed by the database engine as query syntax rather than data.

Exploitation requires an authenticated session. The account must possess API access but does not need the admin or power Splunk role. Successful injection allows the attacker to alter query logic within the scope of the calling user's database permissions. According to the Common Vulnerability Scoring System (CVSS) vector, impact is limited to confidentiality; integrity and availability are not affected.

Root Cause

The root cause is improper neutralization of special elements used in an SQL command [CWE-89]. Splunk Enterprise's REST API concatenates user-supplied filter values into SQL statements without parameterization or input sanitization. Any request parameter used for filter construction becomes an injection sink.

Attack Vector

An authenticated attacker sends a crafted request to a REST API endpoint that accepts a filter parameter. By embedding SQL syntax within the filter value, the attacker forces the backend to execute modified query logic. The vulnerability is exploitable remotely over the network with low complexity, provided the attacker possesses valid low-privileged credentials.

No verified public exploit code is available. Refer to the Splunk Security Advisory SVD-2026-0801 for vendor-supplied technical details.

Detection Methods for CVE-2026-76309

Indicators of Compromise

REST API requests containing SQL metacharacters such as single quotes, --, ;, or UNION in filter parameters
Unexpected database query patterns originating from low-privileged Splunk user sessions
Anomalous response sizes or error messages returned from Splunk REST API endpoints that accept filters

Detection Strategies

Inspect Splunk audit logs (_audit index) for REST API calls from non-admin, non-power users that include SQL syntax in query string parameters
Correlate authentication events with subsequent REST API filter operations to identify low-privileged accounts probing filter endpoints
Enable and review Splunk's internal REST access logging (splunkd_access.log) for suspicious filter values

Monitoring Recommendations

Baseline normal REST API filter usage per user role and alert on deviations
Forward Splunk internal logs to an external security information and event management (SIEM) platform to prevent tampering by a compromised account
Monitor for privilege enumeration attempts preceding filter-based API access

How to Mitigate CVE-2026-76309

Immediate Actions Required

Upgrade Splunk Enterprise to version 10.4.2, 10.2.6, 10.0.9, 9.4.14, or later as applicable to your deployment branch
Audit all non-admin, non-power Splunk accounts and disable unused low-privileged users with REST API access
Review recent REST API audit logs for signs of SQL injection attempts

Patch Information

Splunk has released fixed versions addressing this vulnerability. Consult the Splunk Security Advisory SVD-2026-0801 for the complete list of patched versions and upgrade guidance.

Workarounds

Restrict REST API access to trusted management networks using network-level access controls
Enforce least privilege by removing REST API capabilities from roles that do not require them
If patching is not immediately possible, disable low-privileged accounts that hold REST API permissions until the upgrade is applied

bash

# Verify Splunk Enterprise version
$SPLUNK_HOME/bin/splunk version

# Review roles and their capabilities
$SPLUNK_HOME/bin/splunk list role