# CVE-2026-54134: OctoPrint: File exfiltration possible via query parameters on upload endpoints

> An attacker with upload permissions can exfiltrate arbitrary host files or delete runtime files by exploiting parser differentials in OctoPrint's upload endpoints.

- **Severity:** High 7.0 (`CVSS:4.0/AV:A/AC:L/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 21 Aug 2026
- **Updated:** 26 Aug 2026
- **Also known as:** GHSA-j4h9-pm27-4rfw, PYSEC-2026-2687

## What is CVE-2026-54134?

CVE-2026-54134 is a high-severity path traversal vulnerability in OctoPrint, published on 21 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

OctoPrint provides a web interface for controlling consumer 3D printers. Prior to 1.11.8 and 2.0.0rc3, OctoPrint's custom Tornado upload handler and Flask with Werkzeug parse request parameters differently, allowing an attacker with FILE_UPLOAD permission to inject reserved internal upload fields through query parameters or parser differentials despite the earlier GHSA-m9jh-jf9h-x3h2 fix. The affected endpoints are /api/files/{local|sdcard}, /api/languages, /plugin/backup/restore, and /plugin/pluginmanager/upload_file. An attacker can make OctoPrint treat an arbitrary host file as a temporary upload, move it into a downloadable upload directory, disclose configuration secrets or other readable files, and remove runtime files in a way that can affect a later restart. This issue is fixed in versions 1.11.8 and 2.0.0rc3.

Weakness: CWE-73 (External Control of File Name or Path)

## Which versions are affected by CVE-2026-54134?

5 open source packages ship an affected version, including octoprint and OctoPrint.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `octoprint` | PyPI | All versions | 1.11.8, 2.0.0rc3 |
| `octoprint` | PyPI | All versions | 1.11.8 |
| `octoprint` | PyPI | From 2.0.0rc1 | 2.0.0rc3 |
| `OctoPrint` | PyPI | All versions | 1.11.8 |
| `OctoPrint` | PyPI | From 2.0.0rc1 | 2.0.0rc3 |

## How do I fix CVE-2026-54134?

Upgrade octoprint to a fixed version for your release line: 1.11.8 or 2.0.0rc3.

## Is CVE-2026-54134 being exploited?

There is no known exploitation of CVE-2026-54134 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-54134 and fix it if it is affected.

What it is: CVE-2026-54134 is a high-severity path traversal vulnerability in OctoPrint, published on 21 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-54134 in the wild and no public exploit code.

Affected packages and fixed versions:
- octoprint (PyPI): affected all versions; fixed in 1.11.8, 2.0.0rc3
- octoprint (PyPI): affected all versions; fixed in 1.11.8
- octoprint (PyPI): affected from 2.0.0rc1; fixed in 2.0.0rc3
- OctoPrint (PyPI): affected all versions; fixed in 1.11.8
- OctoPrint (PyPI): affected from 2.0.0rc1; fixed in 2.0.0rc3

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-54134/ (Markdown: https://insights.sbomify.com/CVE-2026-54134/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-54134
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-54134
- OSV: https://osv.dev/vulnerability/CVE-2026-54134

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-54134/
Summaries are generated and may contain mistakes; the official description above is the record.