CVE-2026-55761 PUBLISHED

Portainer: Unauthenticated Restore Endpoint Allows Admin Takeover on Uninitialised Portainer Instances

Assigner: GitHub_M
Reserved: 17.06.2026 Published: 08.07.2026 Updated: 08.07.2026

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.

Metrics

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:H/SI:H/SA:H
CVSS Score: 7.1

Product Status

Vendor portainer
Product portainer
Versions
  • Version >= 2.39.0, < 2.39.4 is affected

References

Problem Types

  • CWE-287: Improper Authentication CWE