NanoMQ: Heap-Buffer-Overflow in `nmq_subinfo_decode()` During MQTT v5 SUBSCRIBE Parsing

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-73863
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-18 17:17:00 UTC
Updated2026-09-24 21:18:35 UTC
DescriptionNanoMQ is an MQTT broker. Prior to 0.24.14, NanoMQ's broker-side MQTT v5 nmq_subinfo_decode() function in nng/src/sp/protocol/mqtt/mqtt_parser.c reuses len_of_varint from the outer Properties Length while parsing each SUBSCRIPTION_IDENTIFIER. A remote client can send a SUBSCRIBE packet with a multi-byte Properties Length and repeated subscription identifiers, causing get_var_integer() to begin at an incorrect offset and read beyond the heap message buffer. The flaw is reachable through the broker receive path and can crash the broker, while the separately reported topic-option off-by-one occurs later and is not this vulnerability. This issue is fixed in version 0.24.14.

Risk And Classification

Primary CVSS: v4.0 7 HIGH from [email protected]

CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS: 0.003530000 probability, percentile 0.263020000 (date 2026-09-25)

Problem Types: CWE-125 | CWE-125 CWE-125: Out-of-bounds Read

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary7HIGHCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:H/E:X/C...
4.0CNADECLARED7HIGHCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:H

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
High
Attack Requirements
None
Privileges Required
None
User Interaction
None
Confidentiality
None
Integrity
None
Availability
None
Sub Conf.
Low
Sub Integrity
Low
Sub Availability
High

CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Nanomq Nanomq affected < 0.24.14 Not specified

References

ReferenceSourceLinkTags
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/f888fe39d6691b253ff9aee598ce58bbe449ab6f [email protected] github.com
github.com/nanomq/nanomq/security/advisories/GHSA-pf97-vm7h-q84m 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
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