# CVE-2026-76403: Improper Certificate Validation through HTTP Event Collector Kerberos Authentication in Splunk Connect for Kafka

> An attacker can read or alter data in transit when Kerberos authentication is used with HTTP Event Collector in Splunk Connect for Kafka.

- **Severity:** High 7.4 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 19 Aug 2026
- **Updated:** 20 Aug 2026
- **Also known as:** GHSA-xf48-ph6x-76rj

## What is CVE-2026-76403?

CVE-2026-76403 is a high-severity vulnerability in Splunk Connect for Kafka, published on 19 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### 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.

Weakness: CWE-295 (Improper Certificate Validation)

## Which versions are affected by CVE-2026-76403?

It affects 1 product.


Products: Splunk Connect for Kafka.

## How do I fix CVE-2026-76403?

No fix has been published for CVE-2026-76403 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-76403 being exploited?

There is no known exploitation of CVE-2026-76403 in the wild and no public exploit code.

## Other vulnerabilities in Splunk Connect for Kafka

- [CVE-2026-76402](https://insights.sbomify.com/CVE-2026-76402/): Server-Side Request Forgery (SSRF) through the REST API in Splunk Connect for Kafka (high 8.2)
- [CVE-2026-76400](https://insights.sbomify.com/CVE-2026-76400/): Denial of Service (DoS) through the REST API in Splunk Connect for Kafka (medium 5.9)
- [CVE-2026-76401](https://insights.sbomify.com/CVE-2026-76401/): Regular Expression Denial of Service (DoS) through the REST API in Splunk Connect for Kafka (medium 5.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-76403 and fix it if it is affected.

What it is: CVE-2026-76403 is a high-severity vulnerability in Splunk Connect for Kafka, published on 19 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-76403 in the wild and no public exploit code.

Affected product: Splunk Connect for Kafka. 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-2026-76403/ (Markdown: https://insights.sbomify.com/CVE-2026-76403/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-76403
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-76403
- OSV: https://osv.dev/vulnerability/CVE-2026-76403

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-76403/
Summaries are generated and may contain mistakes; the official description above is the record.