CVE-2026-61633
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.
What this means for your business
- An attacker can use it remotely, over a network, with an administrator login, but only after tricking someone into an action such as opening a file or a link.
- FIRST's prediction model gives it a 0.3% chance of attack attempts being seen in the next 30 days, ranking above 17% of all known flaws.
What to do
- 1Ask your IT team or provider whether any of your systems use the affected product.
- 2If you do, follow the vendor's guidance. No patch reference has been published yet.
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Scoring
- CVSS
- 2.0 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:N/A:L- Weakness
- CWE-835
- Assigned by
- security-advisories@github.com
Dates
- Published
- 2026-09-18
- Last modified
- 2026-09-18
- Sources
- NVD
References
- https://github.com/nanomq/NanoNNG/commit/fa8d859bb39841e46cfc6cce280d242bd782ad3d
- 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