CVE-2026-55761
Portainer: Unauthenticated Restore Endpoint Allows Admin Takeover on Uninitialised Portainer Instances
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.
INFO
Published Date :
July 8, 2026, 4:16 p.m.
Last Modified :
July 10, 2026, 5:48 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Update Portainer CE to version 2.39.4 or later.
- Update Portainer CE to version 2.43.0 or later.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-55761.
| URL | Resource |
|---|---|
| https://github.com/portainer/portainer/commit/49f19107cf9a3540cbe406c9eb7f24390e1af02b | Patch |
| https://github.com/portainer/portainer/commit/d2b56efcb4e43c4168bb6688eee9f6bf22867312 | Patch |
| https://github.com/portainer/portainer/issues/2770 | Issue Tracking |
| https://github.com/portainer/portainer/releases/tag/2.39.4 | Release Notes |
| https://github.com/portainer/portainer/releases/tag/2.43.0 | Release Notes |
| https://github.com/portainer/portainer/security/advisories/GHSA-x626-fcwx-f5pc | Exploit Mitigation Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-55761 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-55761
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-55761 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-55761 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jul. 10, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N Added CWE NVD-CWE-noinfo Added CPE Configuration OR *cpe:2.3:a:portainer:portainer:*:*:*:*:community:*:*:* versions from (including) 2.39.0 up to (excluding) 2.39.4 *cpe:2.3:a:portainer:portainer:*:*:*:*:community:*:*:* versions from (including) 2.40.0 up to (excluding) 2.43.0 Added Reference Type GitHub, Inc.: https://github.com/portainer/portainer/commit/49f19107cf9a3540cbe406c9eb7f24390e1af02b Types: Patch Added Reference Type GitHub, Inc.: https://github.com/portainer/portainer/commit/d2b56efcb4e43c4168bb6688eee9f6bf22867312 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/portainer/portainer/issues/2770 Types: Issue Tracking Added Reference Type GitHub, Inc.: https://github.com/portainer/portainer/releases/tag/2.39.4 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/portainer/portainer/releases/tag/2.43.0 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/portainer/portainer/security/advisories/GHSA-x626-fcwx-f5pc Types: Exploit, Mitigation, Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 08, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-55761', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-07-08T15:51:27.827566Z'} -
New CVE Received by [email protected]
Jul. 08, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'portainer', 'product': 'portainer', 'versions': [{'status': 'affected', 'version': '>= 2.39.0, < 2.39.4'}]}] Added 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. Added CVSS V4.0 AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-287 Added Reference https://github.com/portainer/portainer/commit/49f19107cf9a3540cbe406c9eb7f24390e1af02b Added Reference https://github.com/portainer/portainer/commit/d2b56efcb4e43c4168bb6688eee9f6bf22867312 Added Reference https://github.com/portainer/portainer/issues/2770 Added Reference https://github.com/portainer/portainer/releases/tag/2.39.4 Added Reference https://github.com/portainer/portainer/releases/tag/2.43.0 Added Reference https://github.com/portainer/portainer/security/advisories/GHSA-x626-fcwx-f5pc