OctoPrint Vulnerable to Denial of Service through malformed HTTP request in OctoPrint
Impact
OctoPrint versions up until and including 1.11.1 contain a vulnerability that allows any unauthenticated attacker to send a manipulated broken multipart/form-data request to OctoPrint and through that make the web server component become unresponsive. This could be used to effectively run a denial of service attack on the OctoPrint server.
Patches
The vulnerability has been patched in version 1.11.2.
Workaround
OctoPrint administrators are once more reminded to not make OctoPrint available on hostile networks (e.g. the internet), regardless of whether this vulnerability is patched or not.
Details
The issue can be triggered by a broken multipart/form-data request lacking an end boundary to any of OctoPrint's endpoints implemented through the octoprint.server.util.tornado.UploadStorageFallbackHandler request handler. The request handler will get stuck in an endless busy loop, looking for a part of the request that will never come. As Tornado is single-threaded, that will effectively block the whole web server.
The fix adds detection of invalid requests like that and ensures they are handled gracefully with an HTTP 400 Bad Request response.
Credits
This vulnerability was discovered and responsibly disclosed to OctoPrint by Jacopo Tediosi.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | octoprint | < 1.11.2 | 1.11.2 |
References
- https://github.com/OctoPrint/OctoPrint/security/advisories/GHSA-9wj4-8h85-pgrw
- https://nvd.nist.gov/vuln/detail/CVE-2025-48879
- https://github.com/OctoPrint/OctoPrint/commit/c9c35c17bd820f19c6b12e6c0359fc0cfdd0c1ec
- https://github.com/OctoPrint/OctoPrint
- https://pypi.org/project/octoprint
- https://github.com/advisories/GHSA-9wj4-8h85-pgrw
- CVSS vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- Weakness (CWE)
CWE-140, CWE-835- Platform
- Python (PyPI)
- Package
octoprint- Disclosed
- 10.06.2025
- Updated
- 11.10.2026 13:19
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2026-1713 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-9wj4-8h85-pgrw - CC BY 4.0
Vulnerability history: octoprint
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 24
- First → latest
- 05.2021 06.2026
- Without a fix
- 1
- Exploited in attacks
- 0
Severity breakdown
- Critical 1
- High 8
- Medium 13
- Low 2
Disclosures per year
- 2021: 2
- 2022: 8
- 2023: 1
- 2024: 5
- 2025: 5
- 2026: 3
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OctoPrint Vulnerable to Denial of Service through malformed HTTP request in OctoPrint this entry
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