CVE-2026-61633

NanoMQ: Infinite Loop in UNSUBSCRIBE Decoder Leading to Remote DoS

LOW
2
CVSS Score
Published: September 18, 2026 at 04:18 PM UTC
Updated: September 18, 2026 at 06:17 PM UTC
1 product affected across 1 vendorNanomq

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Severity
LOW2
Exploit prediction
EPSS 0.3%
SSVC
PoC

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 0.24.14
Affected range stops below 0.24.14, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

2LOWGitHub_M
Attack Vector
NETWORK
Complexity
HIGH
Privileges
HIGH
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
LOW
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-835

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