CVE-2026-73863 Details
Description
NanoMQ 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.
A heap-buffer-overflow vulnerability has been identified in NanoMQ versions through 0.24.12, specifically within the broker-side MQTT v5 subscription handling. The issue arises in the 'nmq_subinfo_decode()' function, where the parser incorrectly processes repeated 'SUBSCRIPTION_IDENTIFIER' entries. This mismanagement allows a remote client to craft a 'SUBSCRIBE' packet that exploits the vulnerability, leading to an out-of-bounds read and potential crash of the MQTT broker. The flaw is present in the broker's TCP receive path and can also be reached through WebSocket and TLS transports.
Users are advised to upgrade to NanoMQ version 0.24.14 or later, where this vulnerability has been fixed.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Sep 18, 2026CISA-ADP
Assessed Sep 24, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/nanomq/nanomq/security/advisories/GHSA-pf97-vm7h-q84m | CISA-ADP | AdvisoryExploitRemedyVendor |
| https://github.com/nanomq/nanomq/releases/tag/0.24.14 | [email protected] | Release NotesVendor |
| https://github.com/nanomq/nanomq/security/advisories/GHSA-pf97-vm7h-q84m | [email protected] | AdvisoryExploitRemedyVendor |
| https://github.com/nanomq/NanoNNG/commit/f888fe39d6691b253ff9aee598ce58bbe449ab6f | [email protected] | Source CodeVendor |
| https://github.com/nanomq/NanoNNG/pull/1518 | [email protected] | Issue TrackingVendor |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-125 | Out-of-bounds Read | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| NanoMQ | <= 0.24.12 (semver) |
CPE
Remediation
| |
Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Sep 24, 2026 | CVE Modified | CISA-ADP |
| Sep 18, 2026 | New CVE Received | [email protected] |