Remote Code Execution (RCE) through Deserialization of Untrusted Data in Splunk MCP Server app
Summary
| CVE | CVE-2026-76404 |
|---|---|
| State | PUBLISHED |
| Assigner | cisco |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-08-19 22:17:27 UTC |
| Updated | 2026-08-20 16:18:16 UTC |
| Description | In Splunk MCP Server app versions below 1.2.1, a user who holds the "admin" Splunk role could execute arbitrary commands on the underlying operating system. The vulnerability is possible because of missing input validation in the app's credential management component, which deserializes stored data without checking whether the content is of the expected type. |
Risk And Classification
Primary CVSS: v3.1 9.1 CRITICAL from [email protected]
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
EPSS: 0.005610000 probability, percentile 0.441790000 (date 2026-08-25)
Problem Types: CWE-502 | CWE-502 The application deserializes untrusted data without sufficiently verifying that the resulting data will be valid.
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 9.1 | CRITICAL | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H |
| 3.1 | CNA | CVSS | 9.1 | CRITICAL | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H |
CVSS v3.1 Breakdown
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Splunk | Splunk MCP Server App | affected 1.2 1.2.1 custom | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| advisory.splunk.com/advisories/SVD-2026-0808 | [email protected] | advisory.splunk.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Kuniyoshi Noguchi (KuniNogu) (en)
Additional Advisory Data
Solutions
CNA: Upgrade each affected Splunk app or add-on to the applicable fixed version listed in Product Status.
Workarounds
CNA: Turn off or remove the Splunk MCP Server app. For more information see [Manage app and add-on objects](https://help.splunk.com/en/splunk-enterprise/administer/admin-manual/10.2/meet-splunk-apps/manage-app-and-add-on-objects) in the Splunk documentation.