Use-after-free vulnerability in the mg_cgi_ev_handler function in mongoose.c in Cesanta Mongoose Embedded Web Server Library 6.13 and earlier allows a denial of service (application crash) or remote code execution.

In Cesanta Mongoose 6.13, a SIGSEGV exists in the mongoose.c mg_mqtt_add_session() function.

An exploitable arbitrary memory read vulnerability exists in the MQTT packet-parsing functionality of Cesanta Mongoose 6.13. It is a heap-based buffer over-read in mg_mqtt_next_subscribe_topic. A specially crafted MQTT SUBSCRIBE packet can cause an arbitrary out-of-bounds memory read potentially resulting in information disclosure and denial of service. An attacker needs to send a specially crafted MQTT packet over the network to trigger this vulnerability.

An exploitable arbitrary memory read vulnerability exists in the MQTT packet-parsing functionality of Cesanta Mongoose 6.13. It is a heap-based buffer over-read in a parse_mqtt getu16 call. A specially crafted MQTT SUBSCRIBE packet can cause an arbitrary out-of-bounds memory read potentially resulting in information disclosure and denial of service. An attacker needs to send a specially crafted MQTT packet over the network to trigger this vulnerability.

The mg_handle_cgi function in mongoose.c in Mongoose 6.11 allows remote attackers to cause a denial of service (heap-based buffer over-read and application crash, or NULL pointer dereference) via an HTTP request, related to the mbuf_insert function.

An exploitable stack buffer overflow vulnerability exists in the MQTT packet parsing functionality of Cesanta Mongoose 6.8. A specially crafted MQTT SUBSCRIBE packet can cause a stack buffer overflow resulting in remote code execution. An attacker needs to send a specially crafted MQTT packet over the network to trigger this vulnerability.

An exploitable use-after-free vulnerability exists in the HTTP server implementation of Cesanta Mongoose 6.8. An ordinary HTTP POST request with a CGI target can cause a reuse of previously freed pointer potentially resulting in remote code execution. An attacker needs to send this HTTP request over the network to trigger this vulnerability.

An exploitable NULL pointer dereference vulnerability exists in the MQTT packet parsing functionality of Cesanta Mongoose 6.8. An MQTT SUBSCRIBE packet can cause a NULL pointer dereference leading to server crash and denial of service. An attacker needs to send a specially crafted MQTT packet over the network to trigger this vulnerability.

An exploitable memory corruption vulnerability exists in the Websocket protocol implementation of Cesanta Mongoose 6.8. A specially crafted websocket packet can cause a buffer to be allocated while leaving stale pointers which leads to a use-after-free vulnerability which can be exploited to achieve remote code execution. An attacker needs to send a specially crafted websocket packet over the network to trigger this vulnerability.

An exploitable memory corruption vulnerability exists in the Websocket protocol implementation of Cesanta Mongoose 6.8. A specially crafted websocket packet can cause an integer overflow, leading to a heap buffer overflow and resulting in denial of service and potential remote code execution. An attacker needs to send a specially crafted websocket packet over network to trigger this vulnerability.