Portainer up to 2.42.9 Initialization/Restore initialization

Summaryinfo

A vulnerability labeled as critical has been found in Portainer up to 2.42.9. Affected by this vulnerability is an unknown functionality of the component Initialization/Restore Handler. Such manipulation leads to initialization. This vulnerability is traded as CVE-2026-55761. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Portainer up to 2.42.9. Affected by this issue is an unknown part of the component Initialization/Restore Handler. The manipulation with an unknown input leads to a initialization vulnerability. Using CWE to declare the problem leads to CWE-665. The product does not initialize or incorrectly initializes a resource, which might leave the resource in an unexpected state when it is accessed or used. Impacted is confidentiality, integrity, and availability. CVE summarizes:

Portainer Community Edition is a lightweight service delivery platform for containerized applications that can be used to manage Docker, Swarm, Kubernetes and ACI environments. In versions 2.39.0 through 2.39.3 and 2.40.0 until 2.43.0, unauthenticated restore and administrator initialization endpoints (/api/restore and /api/users/admin/init) remain accessible during the five-minute setup window for uninitialized instances, allowing a network attacker to restore a crafted backup or create the first administrator account and gain full administrative access. This issue is fixed in versions 2.39.4 and 2.43.0.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-55761 since 06/17/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are neither technical details nor an exploit publicly available.

Upgrading to version 2.39.4 or 2.43.0 eliminates this vulnerability.

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Productinfo

Name

• Portainer

Version

• 2.42.0
• 2.42.1
• 2.42.2
• 2.42.3
• 2.42.4
• 2.42.5
• 2.42.6
• 2.42.7
• 2.42.8
• 2.42.9

Website

• Product: https://github.com/portainer/portainer/

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