Splunk Enterprise: Missing Authentication for Critical Functionality
CVE-2026-76268 is a critical-severity missing authentication for critical functionality vulnerability in Splunk Enterprise from Splunk, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 10.4.3, 10.2.7 as the first without the flaw, so updating Splunk Enterprise to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 5.75% chance of exploitation within 30 days, which is in the top 6.82% of all scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Splunk Enterprise to 10.4.3 or 10.2.7, whichever matches your release line, or a later version.
- Update Splunk to 10.2.7 or 10.4.3, whichever matches your release line, or a later version.
- Read the advisory on advisory.splunk.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Splunk | Splunk Enterprise | 10.4 up to, but not including, 10.4.3; 10.2 up to, but not including, 10.2.7 | 10.4.3, 10.2.7 |
| Splunk | Splunk | 10.2.0 up to, but not including, 10.2.7; 10.4.0 up to, but not including, 10.4.3 | 10.2.7, 10.4.3 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (cisco.com).
Official description
In Splunk Enterprise versions below 10.4.3 and 10.2.7, an unauthenticated user with network access to the Patroni Representational State Transfer (REST) Application Programming Interface (API) on a search head cluster member could execute attacker-controlled operating-system commands. The vulnerability is possible because this interface does not require authentication for critical configuration operations. For more information see Sidecar configuration settings (https://help.splunk.com/en/data-management/splunk-enterprise-admin-manual/10.2/splunk-sidecars/sidecar-configuration-settings) in the Splunk documentation. Splunk Enterprise versions 10.0.x and 9.4.x are not affected.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Missing Authentication for Critical Functionality
The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.
How developers prevent this class of flaw
- For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using libraries with authentication capabilities such as OpenSSL or the ESAPI Authenticator.
- When storing data in the cloud (e.g., S3 buckets, Azure blobs, Google Cloud Storage, etc.), use the provider's controls to require strong authentication for users who should be allowed to access the data.
More Missing Authentication for Critical Functionality vulnerabilities (CWE-306)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other vulnerabilities in Splunk Enterprise
- 9.9 Critical severity
- 9.8 Critical severity
- 8.8 High severity
- 9.9 Critical severity
- 8.8 High severity
- 7.2 High severity
Recent Missing Authentication for Critical Functionality vulnerabilities
- 9.8 Critical severity
- 9.8 Critical severity
- 7.2 High severity
- 9.4 Critical severity
- 8.6 High severity
- 9.8 Critical severity
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