CVE-2026-55761

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

MEDIUM
5.9
CVSS Score
Published: July 8, 2026 at 03:03 PM UTC
Updated: July 10, 2026 at 05:48 PM UTC
1 product affected across 1 vendorPortainer

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Severity
MEDIUM5.9
Exploit prediction
EPSS 0.5%
SSVC
No known exploit

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 2.39.42.39.0 ≤ v < 2.39.42.40.0 ≤ v < 2.43.0
Affected range stops below 2.39.4, so it looks safe — our inference, not a vendor statement

References (6)

x_refsource_CONFIRMExploitMitigationVendor Advisory
Source: cverecord
https://github.com/portainer/portainer/security/advisories/GHSA-x626-fcwx-f5pc
x_refsource_MISCIssue Tracking
Source: cverecord
https://github.com/portainer/portainer/issues/2770
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/portainer/portainer/releases/tag/2.39.4
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/portainer/portainer/releases/tag/2.43.0

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-287NVD-CWE-noinfo

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