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.

Use-after-free vulnerability in the mg_http_multipart_wait_for_boundary function in mongoose.c in Cesanta Mongoose Embedded Web Server Library 6.7 and earlier and Mongoose OS 1.2 and earlier allows remote attackers to cause a denial of service (crash) via a multipart/form-data POST request without a MIME boundary string.

Cesanta Software Mongoose-OS Integer Overflow or Wraparound

Cesanta Software Mongoose-OS v2.17.0 is vulnerable to integer wrap-around in function mm_malloc. This improper memory assignment can lead to arbitrary memory allocation, resulting in unexpected behavior such as a crash or a remote code injection/execution.

The HTTP server in Mongoose before 7.10 accepts requests containing negative Content-Length headers. By sending a single attack payload over TCP, an attacker can cause an infinite loop in which the server continuously reparses that payload, and does not respond to any other requests.

Cesanta Mongoose MQTT Message Parsing Heap Overflow

Due to a failure in validating the length of a provided MQTT_CMD_PUBLISH parsed message with a variable length header, Cesanta Mongoose, an embeddable web server, version 7.10 is susceptible to a heap-based buffer overflow vulnerability in the default configuration. Version 7.9 and prior does not appear to be vulnerable. This issue is resolved in version 7.11.

Arbitrary File Write

This affects the package cesanta/mongoose before 7.6. The unsafe handling of file names during upload using mg_http_upload() method may enable attackers to write files to arbitrary locations outside the designated target folder.

In mjs_json.c in Cesanta MongooseOS mJS 1.26, a maliciously formed JSON string can trigger an off-by-one heap-based buffer overflow in mjs_json_parse, which can potentially lead to redirection of control flow. NOTE: the original reporter disputes the significance of this finding because "there isn’t very much of an opportunity to exploit this reliably for an information leak, so there isn’t any real security impact."

The mg_tls_init function in Cesanta Mongoose HTTPS server 7.0 (compiled with OpenSSL support) is vulnerable to remote OOB write attack via connection request after exhausting memory pool.

The mg_tls_init function in Cesanta Mongoose HTTPS server 7.0 and 6.7-6.18 (compiled with mbedTLS support) is vulnerable to remote OOB write attack via connection request after exhausting memory pool.

The mg_http_serve_file function in Cesanta Mongoose HTTP server 7.0 is vulnerable to remote OOB write attack via connection request after exhausting memory pool.

Buffer overflow in mg_resolve_from_hosts_file in Mongoose 6.18, when reading from a crafted hosts file.

A buffer overflow vulnerability exists in the mg_get_http_header function in Cesanta Mongoose 6.18 due to a lack of bounds checking. A crafted HTTP header can exploit this bug. NOTE: a committer has stated "this will not happen in practice.

An integer overflow in parse_mqtt in mongoose.c in Cesanta Mongoose 6.16 allows an attacker to achieve remote DoS (infinite loop), or possibly cause an out-of-bounds write, by sending a crafted MQTT protocol packet.

mq_parse_http in mongoose.c in Mongoose 6.15 has a heap-based buffer over-read.

An issue was discovered in Mongoose before 6.15. The parse_mqtt() function in mg_mqtt.c has a critical heap-based buffer overflow.

An invalid read of 8 bytes due to a use-after-free vulnerability in the mg_http_free_proto_data_cgi function call 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.

An invalid write of 8 bytes due to a use-after-free vulnerability in the mg_http_free_proto_data_cgi function call 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.

An invalid read of 8 bytes due to a use-after-free vulnerability during a "return" in the mg_http_get_proto_data 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.

An invalid read of 8 bytes due to a use-after-free vulnerability during a "NULL test" in the mg_http_get_proto_data 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.

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.