What’s Vulnerable › Vulnerabilities

CVE-2026-55761: Portainer: Unauthenticated Restore Endpoint Allows Admin Takeover on Uninitialised Portainer Instances

• Severity: medium (CVSS 5.9 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-07-08 · updated 2026-07-10
• Weakness: CWE-287

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. 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.

Affected products

• portainer: from 2.39.0 before 2.39.4; from 2.40.0 before 2.43.0 — fixed in 2.39.4, 2.43.0

How to fix

Upgrade to a fixed version: portainer 2.39.4, 2.43.0. Check the vendor advisory for mitigations.

References

• https://github.com/portainer/portainer/commit/49f19107cf9a3540cbe406c9eb7f24390e1af02b
• https://github.com/portainer/portainer/commit/d2b56efcb4e43c4168bb6688eee9f6bf22867312
• https://github.com/portainer/portainer/issues/2770
• https://github.com/portainer/portainer/releases/tag/2.39.4
• https://github.com/portainer/portainer/releases/tag/2.43.0
• https://github.com/portainer/portainer/security/advisories/GHSA-x626-fcwx-f5pc

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