portainer Community Edition up to 2.33.7/2.39.1/2.40.x /api/stacks/{id}/file link following

Summaryinfo

A vulnerability identified as critical has been detected in portainer Community Edition up to 2.33.7/2.39.1/2.40.x. The affected element is an unknown function of the file /api/stacks/{id}/file. Performing a manipulation results in link following. This vulnerability is identified as CVE-2026-44881. The attack can be initiated remotely. There is not any exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, was found in portainer Community Edition up to 2.33.7/2.39.1/2.40.x. This affects some unknown functionality of the file /api/stacks/{id}/file. The manipulation with an unknown input leads to a link following vulnerability. CWE is classifying the issue as CWE-59. The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE 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 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.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-44881 since 05/07/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 2.33.8, 2.39.2 or 2.41.0 eliminates this vulnerability.

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Productinfo

Vendor

• portainer

Name

• Community Edition

Version

• 2.0
• 2.1
• 2.2
• 2.3
• 2.4
• 2.5
• 2.6
• 2.7
• 2.8
• 2.9
• 2.10
• 2.11
• 2.12
• 2.13
• 2.14
• 2.15
• 2.16
• 2.17
• 2.18
• 2.19
• 2.20
• 2.21
• 2.22
• 2.23
• 2.24
• 2.25
• 2.26
• 2.27
• 2.28
• 2.29
• 2.30
• 2.31
• 2.32
• 2.33
• 2.33.0
• 2.33.1
• 2.33.2
• 2.33.3
• 2.33.4
• 2.33.5
• 2.33.6
• 2.33.7
• 2.34
• 2.35
• 2.36
• 2.37
• 2.38
• 2.39
• 2.39.0
• 2.39.1
• 2.40

CPE 2.3info

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CPE 2.2info

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