# CVE-2026-44885: portainer Path Traversal — Fixed in 2.33.8

🐹

🐹 Go

Not in CISA KEV

MEDIUM severity

# CVE-2026-44885 — portainer

MEDIUM [Fix: portainer/portainer-suite#1875](https://github.com/portainer/portainer-suite/pull/1875)

CVE-2026-44885 is a medium-severity (CVSS 5.5) Path Traversal vulnerability in github.com/portainer/portainer. A fix is available for github.com/portainer/portainer — see the affected versions and patch details below.

Portainer: Path traversal in backup archive extraction allows arbitrary file write

Also known as[GHSA-m8fg-67j7-cx4v](/vulnerability/GHSA-m8fg-67j7-cx4v)GO-2026-5498

Published

May 28, 2026

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 7, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

## Exploitation Status

### No confirmed exploitation observed yet

-   CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-44885.

## EPSS Exploitation Probability

[via FIRST.org ↗](https://www.first.org/epss/)

0.6%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs49th percentile — riskier than 49% of all scored CVEsHighest risk

0.00%0.43%0.87%1.30%0.3%0.6%Jun 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from [FIRST.org EPSS](https://www.first.org/epss/).

## How urgent is this, really

## Where this sits among everything scored

## Real-World Exposure

1 pkg affected

🐹`github.com/portainer/portainer`

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

## Description

#### Summary

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.

### Severity

**Medium**

**CWE-22** — Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Exploitation requires administrator access to Portainer's backup restore endpoint. An administrator who is deceived into restoring a malicious archive, or whose credentials are compromised, can use this path to write files outside the Portainer data directory.

### Affected Versions

The vulnerability exists in every Portainer release prior to 2.39.0 — `ExtractTarGz` has used `filepath.Clean(filepath.Join())` since it was introduced. The fix shipped with 2.39.0 (patched on `develop` before the 2.39 branch cut); 2.34.x–2.38.x STS releases are also affected but are end-of-life and will not receive a fix.

Branch

First vulnerable

Fixed in

2.33.x (LTS)

2.33.0

**2.33.8**

Portainer 2.39.0 and later are not affected — the fix was present from the initial 2.39.0 release. All releases prior to 2.33.0 are end-of-life and will not receive a fix; users on EOL versions should upgrade to a supported release.

### Workarounds

Administrators who cannot immediately upgrade should:

-   **Only restore archives from trusted sources.** Do not restore archives received from untrusted parties or transmitted over unencrypted channels.
-   **Use backup encryption.** Portainer's optional backup encryption requires the correct passphrase to decrypt before extraction; an attacker without the passphrase cannot craft a valid encrypted archive.

Neither of these replaces the fix.

### Affected Code

`ExtractTarGz` in `api/archive/targz.go` constructed output paths without safe containment:

```
// api/archive/targz.go (pre-fix)
case tar.TypeReg:
    p := filepath.Clean(filepath.Join(outputDirPath, header.Name))
```

filepath.Join resolves ../ components lexically and filepath.Clean normalises the result, but neither verifies the final path remains inside outputDirPath. The fix replaces this with filesystem.JoinPaths, which forces all path components to be relative to the trusted root:

```
// api/archive/targz.go (post-fix)
case tar.TypeReg:
    p := filesystem.JoinPaths(outputDirPath, header.Name)
```

#### Impact

-   Arbitrary file write at any path accessible to the Portainer process (typically root in containerised deployments), overriding filesystem boundaries of the data directory.
-   Potential host persistence by writing to cron directories, SSH authorised key files, or executable paths, depending on how the container is configured and what host paths are accessible.

The practical severity is reduced because exploitation requires administrative privileges within Portainer.

### Timeline

-   2026-02-16: Fix merged to develop ([#1875](https://github.com/portainer/portainer-suite/pull/1875)).
-   2026-02-25: 2.39.0 released with fix.
-   2026-05-07: 2.33.8 released with backport fix.

#### Credits

Reported by [Kolega](https://kolega.ai).

## Affected Packages

1 total 1 fixed

Ecosystem

Package

Vulnerable range

Fix

🐹Go

`github.com/portainer/portainer` 

≥ 2.33.0&&< 2.33.8

2.33.8`go get github.com/portainer/portainer@v2.33.8`

## Affected Products

1 product · 1 configurations

Application

`portainer`portainer

≥ 2.33.0 && < 2.33.8

range

## Detection & mitigation playbook

Open-source dependency

1.  ### Detect
    
    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/portainer/portainer, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
    
2.  ### Fix
    
    Update github.com/portainer/portainer to 2.33.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-44885 is resolved across your whole dependency graph.
    
3.  ### Workarounds
    
    Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.
    

## Frequently Asked Questions

\### Summary 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. ## Severity \*\*Medium\*\* \*\*CWE-22\*\* — Improper Limitation of a Pathname to a Res

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