CVE-2025-48879

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.

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.

### 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.

### 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.

Las versiones de OctoPrint hasta la 1.11.1 inclusive contienen una vulnerabilidad que permite a cualquier atacante no autenticado enviar una solicitud multipart/form-data manipulada y rota a OctoPrint, provocando así que el componente del servidor web deje de responder. El problema puede desencadenarse por una solicitud multipart/form-data rota que no tenga un límite final en ninguno de los endpoints de OctoPrint implementados mediante el controlador de solicitudes octoprint.server.util.tornado.UploadStorageFallbackHandler. El controlador de solicitudes se atascará en un bucle de actividad interminable, buscando una parte de la solicitud que nunca llegará. Dado que Tornado es de un solo subproceso, esto bloqueará efectivamente todo el servidor web. La vulnerabilidad se ha corregido en la versión 1.11.2.