CVE-2026-55761Network attack vector

Unauthenticated admin takeover via exposed setup endpoints

Published Jul 8, 2026 · Updated Jul 8, 2026

Improper authentication in Portainer Community Edition allows remote attackers to gain administrative access during initial setup. In versions 2.39.0 through 2.39.3 and 2.40.0 before 2.43.0, the public restore and administrator-initialization handlers accept requests without authentication or a setup secret, enabling a crafted database restore or creation of the first administrator. The instance must be uninitialized, network-reachable, and within the five-minute startup window; successful exploitation grants full control of Portainer and its connected environments.

CVSS severity7.1
High
EPSS probability0.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authentication in Portainer Community Edition allows remote attackers to gain administrative access during initial setup. In versions 2.39.0 through 2.39.3 and 2.40.0 before 2.43.0, the public restore and administrator-initialization handlers accept requests without authentication or a setup secret, enabling a crafted database restore or creation of the first administrator. The instance must be uninitialized, network-reachable, and within the five-minute startup window; successful exploitation grants full control of Portainer and its connected environments.

The record

CVE
CVE-2026-55761
Published
Jul 8, 2026
Updated
Jul 8, 2026
Vendor
Portainer
Product
Portainer Community Edition
Classifications
CWE-287, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 8, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 2.39.0, < 2.39.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Portainer · Portainer Community Editionversion=>= 2.39.0, < 2.39.4

Published CVSS scores

7.1GitHub, Inc.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
5.9NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-287Improper Authentication
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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