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Strimzi Kafka OperatorApplication · Linuxfoundation

CVE-2026-27134

HIGH · 8.1 CVSS v3.1 Published 2026-02-21
Fix available
A fix is available. Upgrade to 0.50.1 or later.
See remediation →
90/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

In Strimzi versions 0.49.0-0.50.0, when using a custom Cluster or Clients CA with a multistage CA chain (multiple CAs), the system incorrectly trusts ALL CAs in the chain for mTLS authentication. This allows users with certificates signed by ANY CA in the chain to authenticate, creating an authentication bypass where only the leaf/intermediate CA should be trusted.

MitigationUpgrade to Strimzi 0.50.1 or later. As a workaround, configure only the single CA that should be trusted rather than providing the full CA chain.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Strimzi Kafka OperatorApplication
Affected:>= 0.49.0, < 0.50.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Strimzi operator version
    Run 'kubectl get deployment strimzi-cluster-operator -n <namespace> -o jsonpath="{.spec.template.spec.containers[0].image}"' or check the operator's pod image tag
    Affected if Version is 0.49.0 through 0.50.0 (inclusive) and not patched to 0.50.1 or later
  2. Check for custom Cluster CA configuration
    Inspect the Strimzi Kafka CR or cluster config for 'clusterIssuer' or custom CA certificate configuration within the Kafka cluster spec, typically under 'spec.clusterCa' or related TLS settings
    Affected if A custom Cluster CA is configured with a multi-stage CA chain (multiple intermediate CAs bundled together)
  3. Check for custom Clients CA configuration
    Inspect the Kafka CR for custom Clients CA configuration, typically under 'spec.clientsCa' or related client TLS settings, looking for certificate bundles
    Affected if A custom Clients CA is configured with a multi-stage CA chain (multiple intermediate CAs bundled together)
  4. Verify CA chain structure
    Examine the CA certificate bundle provided to Strimzi by running 'kubectl get secret <ca-secret> -n <namespace> -o yaml' and inspecting the certificate chain for multiple 'BEGIN CERTIFICATE' entries
    Affected if The CA secret contains more than one CA certificate (a chain of intermediate CAs rather than a single CA)

You are affected if Strimzi version 0.49.0-0.50.0 is running AND custom Cluster CA or Clients CA is configured with a multi-stage CA chain (multiple intermediate CAs), allowing certificates from any CA in the chain to authenticate rather than only the leaf CA.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 0.50.1 or later
Fixed in 0.50.1
Interim mitigation

Upgrade to Strimzi 0.50.1 or later. As a workaround, configure only the single CA that should be trusted rather than providing the full CA chain.

Recommended fix High confidence

Strimzi Kafka Operator 0.50.1

  1. Upgrade Strimzi Kafka Operator to version 0.50.1 or later
  2. If upgrading is not immediately possible, as a workaround, reconfigure custom Cluster or Clients CA to include only the single CA that should be trusted (instead of the full CA chain with multiple CAs)
Caveat Review release notes for 0.50.1 to check for any other changes that may affect your deployment

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Strimzi Kafka Operator Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing4.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,900
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-27134 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data