CVE-2026-61633

LOW 2.0

NanoMQ: Infinite Loop in UNSUBSCRIBE Decoder Leading to Remote DoS

CVSS Score

2.0

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-835
Vendor	nanomq
Product	nanomq
Published	Sep 18, 2026
Last Updated	Sep 18, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:N/A:L

Attack Vector

Network

Attack Complexity

High

Privileges Required

High

User Interaction

Required

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

Low

Affected Versions

nanomq / nanomq

< 0.24.14

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/nanomq/nanomq/security/advisories/GHSA-m7mp-rr3v-hmhr github.com: https://github.com/nanomq/NanoNNG/pull/1518 github.com: https://github.com/nanomq/NanoNNG/commit/fa8d859bb39841e46cfc6cce280d242bd782ad3d github.com: https://github.com/nanomq/nanomq/releases/tag/0.24.14