TI-2026-32757 Aliases CVE-2026-44882 GHSA-mgq6-4x29-88r3

Portainer: Kubernetes middleware continues after token validation failure, bypassing endpoint authorization

LOW 37CWE-863Published 2026-05-28 · Updated 2026-05-30

Key facts

Attack vector: Network
Privileges required: Low
User interaction: None
Attack complexity: Low
Impact type: Security bypass
Confidentiality · integrity · availability: High · High · None
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-863.

Summary

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 — 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 — for example a user without permission to access a given Kubernetes endpoint — 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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00335 27th percentileScored 2026-11-07

Public exploit Yes 1 exploit referenceTagged by NVD

Fix Fixed portainer (portainer): 2.33.8github.com/portainer/portainer (Go): 2.33.8

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
portainer	portainer	2.33.0 to before 2.33.8	2.33.8	Patch available	CNA
—	github.com/portainer/portainer (Go)	2.33.0 to before 2.33.8	2.33.8	Patch available	GHSA-mgq6-4x29-88r3

portainer Vendorportainer Affected 2.33.0 to before 2.33.8 Fixed in 2.33.8 Patch available CNA
github.com/portainer/portainer (Go) Vendor— Affected 2.33.0 to before 2.33.8 Fixed in 2.33.8 Patch available GHSA-mgq6-4x29-88r3

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:portainer:portainer:::::community:::*	2.33.0 to before 2.33.8	Vulnerable	portainer

cpe:2.3:a:portainer:portainer:*:*:*:*:community:*:*:* Versions 2.33.0 to before 2.33.8 Vulnerable ·portainer

Remediation

Fix · CNA portainer (portainer) Fixed in 2.33.8
Fix · GHSA-mgq6-4x29-88r3 github.com/portainer/portainer (Go) Fixed in 2.33.8 Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2026-44882
2026-10-03 Alias added: GHSA-mgq6-4x29-88r3

References

Exploit 1

https://github.com/portainer/portainer/security/advisories/GHSA-mgq6-4x29-88r3

Advisory 1

https://nvd.nist.gov/vuln/detail/CVE-2026-44882

Other 2

TI-2026-32726 Portainer: Missing authorization on Docker plugin endpoints allows host RCE CVSS 4.0CRITICAL 9.4
TI-2026-32758 Portainer: JWT accepted in URL query leaks tokens to logs and referers CVSS 4.0HIGH 7.7
TI-2026-32727 Portainer: Endpoint security bypass via Swarm service create/update CVSS 4.0CRITICAL 9.4
TI-2020-14859 Portainer 1.24.1 and earlier is affected by incorrect access control that may lead to… CVSS 3.1CRITICAL 9.8
TI-2024-22245 Portainer before 2.20.0 allows redirects when the target is not index.yaml. CVSS 3.1CRITICAL 9.1
TI-2018-13786 A vulnerability was found in Portainer before 1.20.0. CVSS 3.0CRITICAL 9.8

See all 25 →

Sources

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