CVE-2025-48879: OctoPrint Vulnerable to Denial of Service through malformed HTTP request
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.
Other sources
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. 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 vulnerability has been patched in version 1.11.2.
— MITRE
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2025-48879?
CVE-2025-48879 has a high severity as it allows unauthenticated attackers to potentially disrupt the web server component.
How do I fix CVE-2025-48879?
To fix CVE-2025-48879, upgrade OctoPrint to version 1.11.2 or later.
What versions are affected by CVE-2025-48879?
CVE-2025-48879 affects all versions of OctoPrint up to and including 1.11.1.
Can CVE-2025-48879 be exploited remotely?
Yes, CVE-2025-48879 can be exploited remotely by an unauthenticated attacker.
What kind of attack does CVE-2025-48879 facilitate?
CVE-2025-48879 facilitates denial-of-service attacks by making the OctoPrint web server unresponsive.