# CVE-2026-76286: Server-Side Request Forgery (SSRF) through Custom API Tools in Splunk MCP Server

> Attackers can capture authentication tokens via SSRF in custom API tools, allowing unauthorized data access and actions as the victim user.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:H/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 7 Oct 2026
- **Updated:** 8 Oct 2026
- **Also known as:** GHSA-mgwr-9j5x-6w4x

## What is CVE-2026-76286?

CVE-2026-76286 is a medium-severity server-side request forgery vulnerability in Splunk MCP Server, published on 7 Oct 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.

### Official description

In Splunk MCP Server versions below 1.2.1, Splunk MCP Server could send the Splunk platform authentication token of a user who runs a custom Application Programming Interface (API) tool to the URL configured for that tool. If another user controls that URL, they could capture the token and use it to access data and perform actions as the user who ran the tool. Successful exploitation requires a user who holds a role that contains the mcp_tool_execute capability to run a custom API tool configured by another user. For more information see Configure the Splunk MCP Server (https://help.splunk.com/en/splunk-enterprise/mcp-server-for-splunk-platform/1.2/configure-the-splunk-mcp-server) and Managing custom tools in Splunk MCP Server (https://help.splunk.com/en/splunk-enterprise/mcp-server-for-splunk-platform/1.2/managing-custom-tools-in-splunk-mcp-server) in the Splunk documentation.

Weakness: CWE-918 (Server-Side Request Forgery)

## Which versions are affected by CVE-2026-76286?


## How do I fix CVE-2026-76286?

No fix has been published for CVE-2026-76286 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-76286 being exploited?

There is no known exploitation of CVE-2026-76286 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-76286 and fix it if it is affected.

What it is: CVE-2026-76286 is a medium-severity server-side request forgery vulnerability in Splunk MCP Server, published on 7 Oct 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-76286 in the wild and no public exploit code.

Affected product: Splunk MCP Server. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-76286/ (Markdown: https://insights.sbomify.com/CVE-2026-76286/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-76286
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-76286
- OSV: https://osv.dev/vulnerability/CVE-2026-76286

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-76286/
Summaries are generated and may contain mistakes; the official description above is the record.