CVE-2026-61633
NanoMQ: Infinite Loop in UNSUBSCRIBE Decoder Leading to Remote DoS
- State
- Published
- Severity
- 2.0 Low
- Published
- Sep 18, 2026
- Updated
- Sep 18, 2026
- Reserved
- Jul 10, 2026
Description
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 2.0 Low | CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:N/A:L | GitHub_M |
Weaknesses
- CWE-835 Loop with Unreachable Exit Condition ('Infinite Loop')
Affected Products
| Product | Versions |
|---|---|
nanomqnanomq |
|
References
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