CVE-2025-48879: OctoPrint Vulnerable to Denial of Service through malformed HTTP request

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-06-10 · updated 2026-06-17
Weakness: CWE-140

Description

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.

Affected products

OctoPrint: before 1.11.2 — fixed in 1.11.2

How to fix

Upgrade to a fixed version: OctoPrint 1.11.2. Check the vendor advisory for mitigations.

References

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