NanoMQ is an MQTT broker. Prior to 0.24.14, the NanoMQ client function nni_mqtt_msg_decode_unsubscribe() in nng/src/supplemental/mqtt/mqtt_codec.c does not handle a failed read_uint16() while counting topics in a malformed UNSUBSCRIBE packet. A zero-length topic followed by trailing data can leave buf.curpos unchanged while topic_count continues to increase, allowing a malicious MQTT broker to hang a connecting MQTT 3.1.1 client, consume CPU and memory, and repeatedly deny service when automatic reconnection is enabled.
The broker-side nmq_unsubinfo_decode path is not affected. This issue is fixed in version 0.24.14.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
High
Difficult to exploit
Privileges Required
High
Admin privileges needed
User Interaction
Required
User action required
Impact Assessment
Confidentiality
None
No data leak
Integrity
None
No data modification
Availability
Low
Partial disruption
CVSS Vector v3.1
Weakness Type (CWE)
References 4
https://github.com/nanomq/NanoNNG/commit/fa8d859bb39841e46cfc6cce280d242bd782ad…
security-advisories@github.com
https://github.com/nanomq/NanoNNG/pull/1518
security-advisories@github.com
https://github.com/nanomq/nanomq/releases/tag/0.24.14
security-advisories@github.com
https://github.com/nanomq/nanomq/security/advisories/GHSA-m7mp-rr3v-hmhr
security-advisories@github.com