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.
- 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
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
Which versions are affected by CVE-2026-54134?
5 open source packages ship an affected version, including octoprint and OctoPrint.
| Package | 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.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-54134 being exploited?
There is no known exploitation of CVE-2026-54134 in the wild and no public exploit code.
Sources
Also known as GHSA-j4h9-pm27-4rfw, PYSEC-2026-2687.