CVE-2026-27134 Strimzi: All CAs from a custom CA chain consisting of multiple CAs are trusted for mTLS user autentication
Strimzi incorrectly trusts all CAs in a multi-stage custom CA chain, allowing unauthorized users with certificates from any chain CA to authenticate via mTLS.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-27134?
CVE-2026-27134 is a high-severity authentication bypass vulnerability in strimzi-kafka-operator, published on 20 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Which versions are affected by CVE-2026-27134?
It affects 1 product.
Products include Linuxfoundation Strimzi Kafka Operator.
How do I fix CVE-2026-27134?
No fix has been published for CVE-2026-27134 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-27134 being exploited?
There is no known exploitation of CVE-2026-27134 in the wild and no public exploit code.
Sources
Also known as GHSA-2qwx-rq6j-8r6j.