CVE-2026-76258 Use of Hard-coded Cryptographic Key through Companion App Registration in Splunk Secure Gateway
A hard-coded key allows non-admin users to register malicious companion apps, redirecting mobile user tokens to attacker-controlled URLs and compromising data.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-76258?
CVE-2026-76258 is a medium-severity vulnerability in Splunk Splunk, published on 19 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
In Splunk Enterprise versions below 10.4.2, 10.2.6, 10.0.9, and 9.4.14, and Splunk Secure Gateway versions below 3.10.10, 3.9.24, and 3.8.71, a user who does not hold the "admin" or "power" Splunk roles could register an arbitrary companion app and cause Splunk Secure Gateway to forward mobile user requests, including tokens that compromise all relevant data available to the affected mobile user, to an attacker-controlled Uniform Resource Locator (URL). The vulnerability is possible because a hard-coded cryptographic key in the Splunk Secure Gateway companion app registration handler allows for arbitrary callback URL registration without restriction. For more information see Define roles on the Splunk platform with capabilities (https://help.splunk.com/en/splunk-enterprise/administer/manage-users-and-security/10.2/manage-splunk-platform-users-and-roles/define-roles-on-the-splunk-platform-with-capabilities) in the Splunk documentation.
Weakness: CWE-321
Which versions are affected by CVE-2026-76258?
It affects 2 products.
Products include Splunk Splunk, Splunk Splunk Secure Gateway.
How do I fix CVE-2026-76258?
No fix has been published for CVE-2026-76258 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-76258 being exploited?
There is no known exploitation of CVE-2026-76258 in the wild and no public exploit code.
Other vulnerabilities in Splunk Splunk
- CVE-2026-20253 Splunk Enterprise Missing Authentication for Critical Function
- CVE-2026-76268 Missing Authentication for Critical Function in the Patroni REST API in Splunk Enterprise
- CVE-2026-76284 Improper Neutralization in Splunk Enterprise
- CVE-2026-76285 Improper Adherence to Coding Standards in Splunk Enterprise
- CVE-2017-17067 Auth bypass in n/a
Sources
Also known as GHSA-3mh4-7c3j-c9mg.