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PatchSiren cyber security CVE debrief

CVE-2026-44850 portainer CVE debrief

Portainer Community Edition versions 2.33.0 through 2.33.7, 2.39.x prior to 2.39.2, and 2.41.0 contain an authorization bypass vulnerability in the environment-level Disable bind mounts for non-administrators security setting. The enforcement logic only validated the legacy HostConfig.Binds array during container creation, while ignoring the equivalent HostConfig.Mounts array. An authenticated non-administrative user with container creation rights could bypass the restriction by submitting a bind-typed mount through HostConfig.Mounts, enabling arbitrary host path mounting into containers. This flaw allows container escape and host filesystem access in environments where the bind mount restriction was explicitly enabled as a security control. The vulnerability is resolved in versions 2.33.8, 2.39.2, and 2.41.0.

Vendor
portainer
Product
Unknown
CVSS
HIGH 8.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-28
Original CVE updated
2026-05-29
Advisory published
2026-05-28
Advisory updated
2026-05-29

Who should care

Organizations using Portainer Community Edition to provide self-service container management to non-administrative users, particularly multi-tenant environments or platforms offering containerized development environments to external users. Security teams relying on Portainer's Disable bind mounts for non-administrators setting as a compensating control for container isolation should prioritize patching.

Technical summary

The vulnerability exists in Portainer's API proxy layer for Docker container creation. When processing container create requests, the security check for the Disable bind mounts for non-administrators setting only inspected HostConfig.Binds, the legacy Docker API field for bind mounts. The modern equivalent field, HostConfig.Mounts, which supports type: bind specifications, was not subject to the same validation. This incomplete input validation (CWE-863) allowed authenticated users to circumvent the security control by structuring bind mount requests using the Mounts array format instead of the Binds array format. The issue affects Docker environment management within Portainer CE and could lead to container escape scenarios where attackers gain read or write access to sensitive host paths including the Docker socket, configuration files, or other containers' filesystems.

Defensive priority

HIGH

Recommended defensive actions

  • Upgrade Portainer Community Edition to version 2.33.8, 2.39.2, or 2.41.0 or later
  • Verify that the Disable bind mounts for non-administrators setting is enabled after upgrade
  • Audit container creation logs for non-administrative users who created containers with bind mounts between affected version deployment and patch application
  • Review and restrict container creation permissions to only trusted users where possible
  • Monitor for anomalous host filesystem access from containers in affected environments
  • Validate that any custom API clients or automation tools use HostConfig.Binds rather than HostConfig.Mounts for bind mount operations to ensure policy enforcement

Evidence notes

Vulnerability description and affected version ranges derived from official CVE record and GitHub Security Advisory. CVSS 3.1 vector confirms network attack vector with low attack complexity, low privileges required, and scope change indicating impact beyond the vulnerable component.

Official resources

2026-05-28