NanoMQ Incorrectly Accepts a Malformed SUBSCRIBE and Can Be Driven into an ASAN-Detectable Out-of-Bounds Read

MITRE NVD CVE.ORG JSON API Print: PDF PDF

Summary

CVECVE-2026-35217
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-20 17:17:06 UTC
Updated2026-07-20 19:17:21 UTC
DescriptionNanoMQ contains a protocol-semantics flaw in its MQTT v5 `SUBSCRIBE` handling: if a subscription entry is missing the final 1-byte `Subscription Options` field, the broker may still accept the malformed packet and install the subscription into internal broker state. Under a specific packet-length construction, the same parser flaw also causes a 1-byte out-of-bounds read that crosses the real heap allocation boundary and is detected by ASAN as a `heap-buffer-overflow`. If the consumed byte happens to look acceptable, NanoMQ may continue and append the malformed subscription entry into its internal `subinfol` state. In that case, a `SUBSCRIBE` packet that should be rejected by MQTT rules is instead treated as a successful subscription. Whether ASAN reports the bug does not depend on MQTT's logical `remain` boundary; it depends on whether the read crosses the real heap allocation boundary of the underlying message buffer. In other words, these are not two unrelated issues. They are two manifestations of the same parsing defect: by default, it appears as a semantic vulnerability, and under suitable input conditions, it also becomes a verifiable out-of-bounds read vulnerability.

Risk And Classification

Primary CVSS: v3.1 6.5 MEDIUM from [email protected]

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

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

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary6.5MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
3.1CNADECLARED6.5MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
High

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Nanomq Nanomq affected <= 0.24.14 Not specified

References

ReferenceSourceLinkTags
github.com/nanomq/nanomq/security/advisories/GHSA-w4xh-p384-w556 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

© CVE.report 2026

Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties, implied or otherwise, with regard to this information or its use. Any use of this information is at the user's risk. It is the responsibility of user to evaluate the accuracy, completeness or usefulness of any information, opinion, advice or other content. EACH USER WILL BE SOLELY RESPONSIBLE FOR ANY consequences of his or her direct or indirect use of this web site. ALL WARRANTIES OF ANY KIND ARE EXPRESSLY DISCLAIMED. This site will NOT BE LIABLE FOR ANY DIRECT, INDIRECT or any other kind of loss.

CVE, CWE, and OVAL are registred trademarks of The MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. This site includes MITRE data granted under the following license.

Free CVE JSON API cve.report/api

CVE.report and Source URL Uptime Status status.cve.report