medium CVSS 5.5

CVE-2026-44885·Docker vulnerability

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.

Severity
medium
Software
Docker
Fixed in
2.33.8
Published
2026-05-28

Affected versions

From: 2.33.0

Until: 2.33.8

Fixed in: 2.33.8

How to fix this CVE

Update Docker to version 2.33.8 or later to patch a path traversal vulnerability in the backup restore feature. This vulnerability allows authenticated attackers with administrative privileges to write files to arbitrary locations on the server by crafting malicious tar.gz archives. Immediately upgrade affected installations and review recent backup restore operations for suspicious activity.

sudo dnf upgrade docker-ce

Defensia detects this vulnerability

WAF mitigation (if patching is not yet possible)

Add this rule to your WAF to block exploitation attempts while you schedule the patch. 

If Portainer or Docker's backup API is exposed over HTTP/HTTPS, implement strict access controls limiting backup restore endpoints to trusted administrative IPs only. Apply rate limiting and authentication token validation on all archive upload/restore operations. Monitor for multipart POST requests containing tar.gz archives with path traversal patterns (../) in file entries.

How to check if you are affected

  1. Run `docker --version` and verify the installed version is 2.33.8 or later (format: Docker version XX.X.X)
  2. Check if Portainer is running alongside Docker: `docker ps | grep -i portainer`; if present, verify its tag/version in the output
  3. Search Docker daemon logs for suspicious tar extraction errors: `journalctl -u docker -n 500 | grep -i 'extract\|tar\|archive'` and look for unexpected path traversal patterns like '../../'
  4. Verify the patch by running `docker version --format '{{json .Server.Version}}'` and confirm it matches or exceeds 27.0.0 (or the distribution's patched release)

FAQ

What is CVE-2026-44885?

CVE-2026-44885 is a path traversal vulnerability in Docker's backup restore functionality that allows authenticated high-privilege users to extract tar.gz archives to arbitrary filesystem locations, potentially overwriting critical system files or planting malware.

Is CVE-2026-44885 being actively exploited?

No, there are no confirmed active exploits or public proof-of-concepts available at this time. However, the vulnerability requires administrative access, limiting its attack surface.

What versions of Docker are affected by CVE-2026-44885?

Docker versions 2.33.0 through 2.33.7 are vulnerable. Version 2.33.8 and later contain the fix.

How do I check if my server is vulnerable to CVE-2026-44885?

Run `docker --version` and compare the version string against 2.33.8. If your version is between 2.33.0 and 2.33.7 inclusive, your installation is vulnerable.

Does Defensia detect CVE-2026-44885?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If Docker is installed on a monitored server, CVE-2026-44885 will appear in your dashboard with remediation steps.

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References

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