CVE-2025-48879

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.

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.

CVE-2025-48879 has a CVSS score of 6.5 (Medium). The vector is reachable from an adjacent network, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.11.2); upgrading removes the vulnerable code path.

Kodem intelligence

The vulnerability has been patched in version 1.11.2.

1. What is CVE-2025-48879? CVE-2025-48879 is a medium-severity security vulnerability in OctoPrint (pip), affecting versions < 1.11.2. It is fixed in 1.11.2.
2. How severe is CVE-2025-48879? CVE-2025-48879 has a CVSS score of 6.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of OctoPrint are affected by CVE-2025-48879? OctoPrint (pip) versions < 1.11.2 is affected.
4. Is there a fix for CVE-2025-48879? Yes. CVE-2025-48879 is fixed in 1.11.2. Upgrade to this version or later.
5. Is CVE-2025-48879 exploitable, and should I be worried? Whether CVE-2025-48879 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2025-48879 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2025-48879? Upgrade OctoPrint to 1.11.2 or later.