External risk intelligence

Portainer Community Edition Swarm API Security Bypass

CVE advisorySeverity: CRITICAL (CVSS 9.4)

CVE-2026-44849

Portainer is a container management platform typically used in internal environments. While it can be internet-exposed, it is not designed to be public-facing for unauthenticated users. The vulnerability requires an authenticated user with permissions to interact with the Docker Swarm service API, limiting the attack surface to those already granted access within the system.

Portainer

2.33.0 to before 2.33.82.34.0 to before 2.39.12.40.0

Halo Surface Signal: 3 out of 5 — possibly public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A vulnerability in Portainer Community Edition allows users with limited privileges to bypass security restrictions when configuring containerized applications, potentially leading to broader system access. This issue affects environments using specific versions of Portainer for managing container orchestration platforms like Docker Swarm. The main concern is confirming if this specific software is in use and if the affected configurations are present.

Bypasses security rules for containers.
Affects container management platforms.
Confirm relevance and exposure.

Attack Path

How an attacker could exploit the issue

An attacker with authenticated access to Portainer could bypass security restrictions when creating Docker Swarm services, potentially leading to elevated privileges or unauthorized actions within the managed environment. The issue stems from specific security settings not being applied consistently across all container creation methods.

Authenticated user with API access.
Creating Docker Swarm services.
Bypassed security settings, potential system compromise.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability could allow a non-admin user to bypass security restrictions configured by an administrator when launching containers. These restrictions, which include settings like privileged mode and host PID namespace, are intended to limit the capabilities of containers launched by non-administrative users. When supported by the advisory, these bypasses could occur when interacting with the Docker Swarm service API, rather than the standard container creation path.

Container configurations.
Bypass of security restrictions.
Unintended container access.

Operational Fix

Recommended remediation, mitigation, and detection steps

The platform and infrastructure teams are likely responsible for managing Portainer Community Edition, with application owners needing to confirm its deployment within their environments. The first practical step is to inventory all Portainer instances, verify their network reachability, and confirm if they are business-critical to prioritize remediation efforts with the appropriate team.

Platform and App teams own remediation.
Verify reachability and criticality of instances.
Plan and coordinate phased updates.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is Portainer Community Edition?

Portainer Community Edition is a web-based management tool that simplifies how teams deploy and oversee containerized applications. It acts as a graphical interface for popular orchestration platforms like Docker, Swarm, and Kubernetes, allowing administrators to manage complex container environments and enforce security policies for users across those systems.

How does CVE-2026-44849 create a security risk?

This vulnerability is classified as Improper Authorization (CWE-862). It occurs because Portainer fails to consistently enforce configured security restrictions when containers are created via the Docker Swarm service API. While administrators may define strict limits—such as blocking privileged mode or specific host access—a user can circumvent these rules when using the Swarm API, gaining more power than intended.

Does this bypass work for all container creations?

No. The security restrictions are correctly applied when users create containers through the standard container creation path in the Portainer interface. The vulnerability is specific to the Docker Swarm service API, meaning standard deployments remain subject to the intended security configurations.

Why should I care about this if my Portainer is internal?

Halo Surface Signal indicates that while Portainer is typically used internally, the vulnerability still requires an authenticated user to exploit the Swarm API. If you have granted users access to the platform, those users could potentially escalate their privileges or bypass controls. Internal environments are not automatically safe if the attacker already has a foothold or legitimate, restricted access to the system.

What should I do first to address this CVE?

Begin by auditing your environment to identify every running instance of Portainer Community Edition. Verify the version of each instance against the affected range to determine if you are running vulnerable software. Once identified, coordinate with your platform and application teams to schedule an update to one of the patched versions—2.33.8, 2.39.2, or 2.41.0—which resolve this inconsistency in security policy enforcement.

References

github.com/portainer/portainer/security/advisories/GHSA-5fxq-qcf…

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.