CVE-2026-44885: Portainer: Path traversal in backup archive extraction allows arbitrary file write

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-05-28 · updated 2026-07-21
Weakness: CWE-22

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, Portainer's backup restore feature accepts a .tar.gz archive and extracts it to a target directory on the server. The extraction function (ExtractTarGz in api/archive/targz.go) constructed output paths using filepath.Clean(filepath.Join(outputDirPath, header.Name)). This combination does not prevent directory traversal — a tar entry named ../../etc/cron.d/evil resolves to a path outside the extraction root, so a crafted archive can write files to arbitrary locations on the server filesystem. This vulnerability is fixed in 2.33.8.

Affected products

portainer: from 2.33.0 before 2.33.8 — fixed in 2.33.8

How to fix

Upgrade to a fixed version: portainer 2.33.8. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2026-44885 or the next vulnerability affects your stack