---
id: "CVE-2026-76288"
kind: "vulnerability"
aliases: ["CVE-2026-76288"]
title: "Splunk Enterprise: one crafted request takes Splunk Web offline"
severity: "high"
cvss: 7.5
epss: 0.00372
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["infrastructure", "self-hosted", "splunk", "web-ui"]
not_affected_if: ["managed-hosting", "splunk-web-disabled"]
published_at: "2026-10-21T23:17:26+00:00"
first_seen_at: "2026-10-23T21:57:29+00:00"
updated_at: "2026-10-25T03:16:22+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-76288", "first_seen_at": "2026-10-23T21:57:29+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-76288", "first_seen_at": "2026-10-24T13:15:54+00:00"}]
---

# Splunk Enterprise: one crafted request takes Splunk Web offline

An unauthenticated attacker can send a single crafted request to the Splunk Web JavaScript logger endpoint, which stops Splunk Web from answering requests. Splunk Web stays down until Splunk Enterprise is restarted, because request-header parsing has no size limit.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed Splunk Enterprise version with `$SPLUNK_HOME/bin/splunk version` and compare it with the fixed releases below.
- Check whether Splunk Web is exposed to untrusted networks, for example on port `8000` from the internet.

## Fix

- Upgrade Splunk Enterprise to `10.4.4`, `10.2.8`, `10.0.11`, or `9.4.16`, matching your release line.
- Until you can upgrade, restrict access to Splunk Web to trusted networks.

## Timeline

- 2026-10-23T21:57:29+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-76288
- 2026-10-24T13:15:54+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-76288

## From the sources

In Splunk Enterprise versions below 10.4.4, 10.2.8, 10.0.11, and 9.4.16, an unauthenticated user could send a single crafted request to the Splunk Web JavaScript logger endpoint and cause Splunk Web to stop responding to requests. Splunk Web remains unavailable until Splunk Enterprise is restarted.
The vulnerability is possible because Splunk Web does not limit request-header parsing before processing the request.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_