TI-2026-40250 Aliases CVE-2026-55761 GHSA-x626-fcwx-f5pc

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

LOW 32CWE-287Published 2026-07-08 · Updated 2026-07-08

Key facts

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

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-287.

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. 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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00493 42nd percentileScored 2026-11-07

Public exploit Yes 1 exploit referenceTagged by NVD

Fix Fixed portainer (portainer): 2.39.4github.com/portainer/portainer (Go): 2.39.4, 2.43.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

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	2.39.0 to before 2.39.4	2.39.4	Patch available	CNA
—	github.com/portainer/portainer (Go)	2.39.0 to before 2.39.4	2.39.4	Patch available	GHSA-x626-fcwx-f5pc
—	github.com/portainer/portainer (Go)	2.40.0 to before 2.43.0	2.43.0	Patch available	GHSA-x626-fcwx-f5pc

portainer Vendorportainer Affected 2.39.0 to before 2.39.4 Fixed in 2.39.4 Patch available CNA
github.com/portainer/portainer (Go) Vendor— Affected 2.39.0 to before 2.39.4 Fixed in 2.39.4 Patch available GHSA-x626-fcwx-f5pc
github.com/portainer/portainer (Go) Vendor— Affected 2.40.0 to before 2.43.0 Fixed in 2.43.0 Patch available GHSA-x626-fcwx-f5pc

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:portainer:portainer:::::community:::*	2.39.0 to before 2.39.4; 2.40.0 to before 2.43.0	Vulnerable	portainer

cpe:2.3:a:portainer:portainer:*:*:*:*:community:*:*:* Versions 2.39.0 to before 2.39.4; 2.40.0 to before 2.43.0 Vulnerable ·portainer

Remediation

Fix · CNA portainer (portainer) Fixed in 2.39.4
Fix · GHSA-x626-fcwx-f5pc github.com/portainer/portainer (Go) Fixed in 2.39.4 Advisory →
Fix · GHSA-x626-fcwx-f5pc github.com/portainer/portainer (Go) Fixed in 2.43.0 Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2026-55761
2026-10-03 Alias added: GHSA-x626-fcwx-f5pc

References

Exploit 1

https://github.com/portainer/portainer/security/advisories/GHSA-x626-fcwx-f5pc

Patch 2

Advisory 1

https://nvd.nist.gov/vuln/detail/CVE-2026-55761

Other 4

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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