NanoMQ: Infinite Loop in UNSUBSCRIBE Decoder Leading to Remote DoS
Summary
| CVE | CVE-2026-61633 |
|---|---|
| State | PUBLISHED |
| Assigner | GitHub_M |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-09-18 17:16:58 UTC |
| Updated | 2026-09-18 18:17:09 UTC |
| 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. |
Risk And Classification
Primary CVSS: v3.1 2 LOW from [email protected]
CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:N/A:L
EPSS: 0.002530000 probability, percentile 0.171240000 (date 2026-09-21)
Problem Types: CWE-835 | CWE-835 CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop')
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 2 | LOW | CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:N/A:L |
| 3.1 | CNA | DECLARED | 2 | LOW | CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:N/A:L |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
HighPrivileges Required
HighUser Interaction
RequiredScope
UnchangedConfidentiality
NoneIntegrity
NoneAvailability
LowCVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:N/A:L
Vendor Declared Affected Products
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/nanomq/nanomq/releases/tag/0.24.14 | [email protected] | github.com | |
| github.com/nanomq/NanoNNG/pull/1518 | [email protected] | github.com | |
| github.com/nanomq/NanoNNG/commit/fa8d859bb39841e46cfc6cce280d242bd782ad3d | [email protected] | github.com | |
| github.com/nanomq/nanomq/security/advisories/GHSA-m7mp-rr3v-hmhr | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | github.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.