Vulnerability 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.
CVSS Score
LOW
Related Weaknesses (CWE)
References
- https://github.com/nanomq/NanoNNG/commit/fa8d859bb39841e46cfc6cce280d242bd782ad3
- https://github.com/nanomq/NanoNNG/pull/1518
- https://github.com/nanomq/nanomq/releases/tag/0.24.14
- https://github.com/nanomq/nanomq/security/advisories/GHSA-m7mp-rr3v-hmhr
- https://github.com/nanomq/nanomq/security/advisories/GHSA-m7mp-rr3v-hmhr
FAQ
What is CVE-2026-61633?
CVE-2026-61633 is a vulnerability with a CVSS score of 2.0 (LOW). 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...
How severe is CVE-2026-61633?
CVE-2026-61633 has been rated LOW with a CVSS base score of 2.0/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-61633?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.