CVE-2026-44882: Portainer authorization bypass in Kubernetes middleware

CVE-2026-44882 · Severity: high · CVSS 8.1 · Published 2026-05-28

Portainer is a management platform used to simplify the deployment and monitoring of containerized applications like Kubernetes. A flaw in its security checks allows a logged-in user to bypass internal authorization and access Kubernetes clusters they are not supposed to manage. This could allow an attacker to view sensitive data, modify application deployments, or gain further access to the corporate infrastructure.

Technologies: github.com/portainer/portainer (Go), Portainer CE, Portainer Community Edition. Vendors: Go, Portainer.

Quick answers

Is CVE-2026-44882 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-44882 being exploited in the wild.
How severe is CVE-2026-44882?
High severity, with a CVSS score of 8.1, published 28 May 2026.
Which products and versions are affected?
github.com/portainer/portainer (Go) >= 2.33.0, < 2.33.8, SEMVER:introduced=0, SEMVER:introduced=2.33.0,fixed=2.33.8; Portainer Business Edition >= 2.33.0, < 2.33.8; Portainer CE >= 2.33.0, < 2.33.8, >= 2.33.0, < 2.33.8; < 2.39.0; Portainer Community Edition >= 2.33.0, < 2.33.8; and 1 more.
Is there a fix for CVE-2026-44882?
Yes. github.com/portainer/portainer (Go): upgrade to 2.33.8 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-44882 attacked?
It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-44882?
Check whether you run github.com/portainer/portainer (Go), Portainer Business Edition, Portainer CE or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • github.com/portainer/portainer (Go): upgrade to 2.33.8 or later
    go get github.com/portainer/portainer@v2.33.8

Technical details

An incorrect authorization vulnerability (CWE-863) exists in Portainer's 'kubeClientMiddleware' within 'api/http/handler/kubernetes/handler.go'. When 'security.RetrieveTokenData' returns an error, the middleware writes an HTTP 403 error response but lacks a 'return' statement, allowing execution to continue with a nil 'tokenData' value. This results in the request being forwarded to the Kubernetes cluster proxy regardless of the failed validation. An attacker with a valid Portainer session can exploit this to read or modify namespaced resources (pods, secrets, config maps) on Kubernetes environments they are not authorized to access. The issue is fixed in versions 2.33.8 and 2.39.0.

Affected products

  • Portainer Portainer CE >= 2.33.0, < 2.33.8; < 2.39.0
  • Portainer Portainer EE >= 2.33.0, < 2.33.8; < 2.39.0

Identifiers

  • CVE-2026-44882
  • GHSA-mgq6-4x29-88r3
  • GO-2026-5505

Timeline

  • 2026-02-16: patched: Fix merged to develop branch
  • 2026-02-25: advisory: Version 2.39.0 released with fix
  • 2026-05-07: advisory: Version 2.33.8 released with backported fix
  • 2026-05-14: disclosed: GitHub Advisory published

References

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