Portainer: Kubernetes middleware continues after token validation failure, bypassing endpoint authorization_CVE-2026-44882

{
    "lastseen": "",
    "description": "Portainer Community Edition is a lightweight service delivery platform for containerized applications that can be used to manage Docker, Swarm, Kubernetes and ACI environments. From 2.33.0 to before 2.33., Portainer proxies requests to Kubernetes clusters through a middleware layer (kubeClientMiddleware) that validates the requesting user's token before forwarding traffic to the cluster. When security.RetrieveTokenData returned an error, the middleware wrote an HTTP 403 response but was missing a return statement \u2014 execution continued into the handler with a nil tokenData value. The Kubernetes endpoints sit behind Portainer's outer AuthenticatedAccess bouncer, so an attacker requires a valid Portainer session. However, a user whose secondary token validation fails in kubeClientMiddleware \u2014 for example a user without permission to access a given Kubernetes endpoint \u2014 would have their request forwarded to the cluster anyway, bypassing the authorization check. The same defect was present in both the CE and EE codebases. This vulnerability is fixed in 2.33.8.",
    "published": "2026-05-28T21:01:31.113Z",
    "modified": "2026-05-28T21:01:31.113Z",
    "type": "cve",
    "title": "Portainer: Kubernetes middleware continues after token validation failure, bypassing endpoint authorization",
    "source": "GitHub_M",
    "references": "https://github.com/portainer/portainer/security/advisories/GHSA-mgq6-4x29-88r3",
    "id": "CVE-2026-44882",
    "bulletinFamily": "",
    "cwe": [
        "CWE-863"
    ],
    "cvelist": null,
    "sourceData": "portainer portainer >= 2.33.0, < 2.33.8",
    "sourceHref": "",
    "cvss": {
        "score": 8.1,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N",
        "version": "3.1"
    },
    "cvss2": [],
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        "confidentialityImpact": "",
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        "availabilityImpact": "",
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    },
    "href": "",
    "category_name": "CVE",
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    "product": "portainer",
    "version": ">= 2.33.0, < 2.33.8",
    "vendor": "portainer",
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}