CVE 8.5 HIGH

Portainer: Arbitrary File Read via Git Symlink Injection in Stack Auto-Update_CVE-2026-44881

8.5 / 10
HIGH
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:H/SA:H

Description

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 supports deploying stacks from Git repositories. When a Git-backed stack is created or updated, Portainer clones the repository using go-git v5, which translates Git blob entries with mode 0o120000 (symlink) into real OS symlinks on the host filesystem via os.Symlink. The only entry blocked from becoming a symlink is .gitmodules; every other path is created as a symlink without validation. Portainer's GET /api/stacks/{id}/file endpoint then reads the stack entry point with os.ReadFile, which follows OS symlinks transparently. A repository containing docker-compose.yml as a symlink to an arbitrary filesystem path causes the symlink target's contents to be returned verbatim in the HTTP response. Any authenticated user with rights to create or update a Git-backed stack — the default configuration in Portainer CE — can read arbitrary files accessible to the Portainer process. This vulnerability is fixed in 2.33.8, 2.39.2, and 2.41.0.

AI Analysis

Arbitrary file read via Git symlink injection in stack auto-update

Basic Information

ID CVE-2026-44881
Source GitHub_M
Published May 28, 2026 at 21:11

Affected Product

Vendor portainer
Product portainer
Version >= 2.33.0, < 2.33.8
Affected Versions portainer portainer >= 2.33.0, < 2.33.8
portainer portainer >= 2.39.0, < 2.39.2
portainer portainer >= 2.40.0, < 2.41.0

CWE Classification

AI Assessment

AI Score 8.5 / 10
AI Severity High
Vendor Portainer
Product Portainer Community Edition
Version 2.33.0 to 2.33.7, 2.39.0 to 2.39.1, 2.40.0 to 2.40.x

References

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