Portainer: Arbitrary File Read via Git Symlink Injection in Stack Auto-Update

Summary

CVECVE-2026-44881
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-05-28 22:16:59 UTC
Updated2026-05-29 15:06:44 UTC
DescriptionPortainer 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.

Risk And Classification

Primary CVSS: v4.0 8.5 HIGH from [email protected]

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS: 0.000580000 probability, percentile 0.184270000 (date 2026-05-29)

Problem Types: CWE-59 | CWE-200 | CWE-59 CWE-59: Improper Link Resolution Before File Access ('Link Following') | CWE-200 CWE-200: Exposure of Sensitive Information to an Unauthorized Actor


VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary8.5HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:H/SA:H/E:X/C...
4.0CNADECLARED8.5HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:H/SA:H

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
Low
User Interaction
None
Confidentiality
High
Integrity
None
Availability
None
Sub Conf.
High
Sub Integrity
High
Sub Availability
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Portainer Portainer affected >= 2.33.0, < 2.33.8 Not specified
CNA Portainer Portainer affected >= 2.39.0, < 2.39.2 Not specified
CNA Portainer Portainer affected >= 2.40.0, < 2.41.0 Not specified

References

ReferenceSourceLinkTags
github.com/portainer/portainer/security/advisories/GHSA-rpgq-m5fp-32wr [email protected] github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis
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