Splunk Connect for Kafka: Improper Certificate Validation
CVE-2026-76403 is a high-severity improper certificate validation vulnerability in Splunk Connect for Kafka from Splunk, with a CVSS 3.1 base score of 7.4 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 2.2.7 as the first without the flaw, so updating Splunk Connect for Kafka to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.24% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Splunk Connect for Kafka to 2.2.7 or a later version.
- Update Connect For Kafka to 2.2.7 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 Connect for Kafka | 2.2 up to, but not including, 2.2.7 | 2.2.7 |
| Splunk | Connect For Kafka | before 2.2.7 | 2.2.7 |
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
- HighSuccess depends on conditions outside the attacker's control.
- 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
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N. Scored by CNA (cisco.com).
Official description
In Splunk Connect for Kafka versions below 2.2.7, an unauthenticated user positioned in the network path could read or alter all relevant data sent from the connector when Kerberos authentication is used with Hypertext Transfer Protocol (HTTP) Event Collector in Splunk Enterprise. The vulnerability is possible because the Kerberos authentication path does not apply the configured certificate validation options when it builds the HTTP client. For more information see Install Splunk Connect for Kafka (https://help.splunk.com/en/data-management/integrate-data-with-add-ons/splunk-connect-for-kafka/2.2/install/install-splunk-connect-for-kafka), Security configurations for Splunk Connect for Kafka (https://help.splunk.com/en/splunk-enterprise/get-data-in/splunk-connect-for-kafka/2.2/configure/security-configurations-for-splunk-connect-for-kafka), and Set up and use HTTP Event Collector with configuration files (https://help.splunk.com/en/splunk-enterprise/get-data-in/get-started-with-getting-data-in/9.4/get-data-with-http-event-collector/set-up-and-use-http-event-collector-with-configuration-files) in the Splunk documentation.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Certificate Validation
The product does not validate, or incorrectly validates, a certificate.
How developers prevent this class of flaw
- Certificates should be carefully managed and checked to assure that data are encrypted with the intended owner's public key.
- If certificate pinning is being used, ensure that all relevant properties of the certificate are fully validated before the certificate is pinned, including the hostname.
More Improper Certificate Validation vulnerabilities (CWE-295)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in Splunk Connect for Kafka
- 8.2 High severity
Recent Improper Certificate Validation vulnerabilities
- 7.4 High severity
- 9.3 Critical severity
- 9.6 Critical severity
- 8.7 High severity
- 8.1 High severity
- 9.1 Critical severity
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