CVE-2026-44849: Portainer has an endpoint security bypass via Swarm service create/update

Should you act?

Critical, preconditions apply

Severe if exploited, but exploitation needs conditions that may not apply to you. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 0.4%, percentile 38: FIRST’s model estimates a 0.4% chance of exploitation activity in the next 30 days, higher than 38% of all scored CVEs (low). EPSS is a probability, not a verdict.
• Needs an account (low (any account)). Exposure depends on who can log in.
• Only applies if your dependency tree includes github.com/portainer/portainer (Go) >= 2.33.0, < 2.33.8, fixed in 2.33.8; github.com/portainer/portainer (Go) >= 2.39.0, < 2.39.2, fixed in 2.39.2; github.com/portainer/portainer (Go) >= 2.40.0, < 2.41.0, fixed in 2.41.0. Check your lockfile, including transitive dependencies.

What it is

Portainer Community Edition is a lightweight service delivery platform for containerized applications that can be used to manage Docker, Swarm, Kubernetes and ACI environments. From 2.33.0 to before 2.33.8, 2.39.2, and 2.41.0, Portainer enforces seven EndpointSecuritySettings restrictions that administrators configure to restrict the container configurations non-admin users can launch: privileged mode, host PID namespace, device mapping, capabilities, sysctls, security-opt (Seccomp / AppArmor), and bind mounts. These restrictions are enforced on the standard container creation path, but several of them are not applied on the Docker Swarm service API. This vulnerability is fixed in 2.33.8, 2.39.2, and 2.41.0.

From the GitHub advisory

Summary

Portainer enforces seven EndpointSecuritySettings restrictions that administrators configure to restrict the container configurations non-admin users can launch: privileged mode, host PID namespace, device mapping, capabilities, sysctls, security-opt (Seccomp / AppArmor), and bind mounts.

The vulnerability is exposed when a non-admin Portainer user (Standard User role, or any role granted endpoint-level access) has been given access to a Docker Swarm endpoint via Portainer RBAC. Admins and users without Swarm endpoint access are not affected.

These restrictions are enforced on the standard container creation path, but several of them are not applied on the Docker Swarm service API:

- POST /services/create — 1 of 7 checks applied. CapabilityAdd, CapabilityDrop, Sysctls, and Privileges (Seccomp / AppArmor) are not parsed from the request body and are forwarded to the Docker daemon without validation. - POST /services/{id}/update — 0 of 7 checks applied. The route dispatches to the generic restrictedResourceOperation, which validates RBAC ownership but does not inspect the request body or call fetchEndpointSecuritySettings().

Weakness type: CWE-862.

Product: github.com/portainer/portainer (Go) · Assigned by: GitHub_M · Published: 2026-05-28

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Attack requirements: none
• Privileges required: low (any account)
• User interaction: none

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation none, automatable yes, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.45% probability of exploitation activity in the next 30 days; percentile 38.

Timeline

• 2026-05-14 — GitHub-reviewed advisory GHSA-5fxq-qcf3-244w published (critical)
• 2026-05-28 — CVE record published by GitHub_M
• 2026-05-29 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-5fxq-qcf3-244w github.com
2. CVE.org record CVE-2026-44849 cve.org
3. NVD entry CVE-2026-44849 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com
3. github.com github.com
4. github.com github.com

Critical Go advisories · Today’s Security Digest