CVE-2026-61633— NanoMQ: Infinite Loop in UNSUBSCRIBE Decoder Leading to Remote DoS
Quick assessment
Affected
nanomq nanomq
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
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 top
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I. Basic Information for CVE-2026-61633
Vulnerability Information
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Vulnerability Title
NanoMQ: Infinite Loop in UNSUBSCRIBE Decoder Leading to Remote DoS
Source: CVE Program / CVE List V5
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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:N/A:L
Source: CVE Program / CVE List V5
Vulnerability Type
不可达退出条件的循环(无限循环)
Source: CVE Program / CVE List V5
Affected Products
II. Public POCs for CVE-2026-61633
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Patches & Fixes for CVE-2026-61633 (2)
Vendor Pages for CVE-2026-61633 (1)
Other References for CVE-2026-61633 (1)
Same Patch Batch · nanomq · 2026-09-18 · 3 CVEs total
| CVE-2026-73863 | 7.0 HIGH | NanoMQ: Heap-Buffer-Overflow in `nmq_subinfo_decode()` During MQTT v5 SUBSCRIBE Parsing |
| CVE-2026-44639 | 3.7 LOW | NanoMQ: O(N²) Denial of Service in MQTT v5 Property Parsing |
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V. Comments for CVE-2026-61633
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