CVE-2026-44881: Portainer Allows Unauthorized Access to Sensitive Files via Git Repositories

Summary

Portainer's Git-backed stack feature allows attackers to read sensitive files on the system by creating a malicious Git repository. This is especially concerning when combined with Portainer's auto-update feature, which can trigger the vulnerability without user interaction. To mitigate this, ensure that only trusted users can create and update Git-backed stacks, and regularly review and update your repositories to prevent malicious changes.

What to do

Update github.com portainer to version 2.33.8.
Update github.com portainer to version 2.39.2.
Update github.com portainer to version 2.41.0.

Affected software

Ecosystem	Vendor	Product	Affected versions
go	github.com	portainer	>= 2.33.0, < 2.33.8 >= 2.39.0, < 2.39.2 >= 2.40.0, < 2.41.0 Fix: upgrade to 2.33.8
–	portainer	portainer	>= 2.33.0, < 2.33.8 >= 2.34.0, < 2.39.2 2.40.0 `cpe:2.3:a:portainer:portainer:::::community:::*`

Original title

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 befor...

Original 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.

ghsa CVSS4.0 8.5

Vulnerability type

CWE-59 Link Following

CWE-200 Information Exposure