Auth bypass in Portainer

CVE-2026-44884

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 and 2.39.1, a missing authorization vulnerability in the Custom Template file endpoint (GET /api/custom_templates/{id}/file) allows any authenticated user to read the file content of any custom template by enumerating sequential integer IDs, bypassing Resource Control access restrictions. Template files may contain environment-specific values such as connection strings, API tokens, or registry credentials that administrators would not expect standard users to read. This vulnerability is fixed in 2.33.8 and 2.39.1.

Vulnerability class: Broken Access Control

Published · last modified .

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.004 (30.2th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 30th percentile — 30.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-44884: held from 0.003 to 0.004.

EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.001

Affected products

  • Portainer — versions >= 2.33.0, < 2.33.8, >= 2.39.0, < 2.39.1

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-44884?
CVE-2026-44884 is a medium-severity vulnerability in Portainer, classified under Missing Authorization. CVSS score: 6.5/10. Published 2026-05-28.
How severe is CVE-2026-44884?
Medium severity. CVSS v3 base score is 6.5 out of 10.