Out-of-Bounds Read Vulnerability in NanoMQ MQTT Broker
CVE-2026-21888

7.5HIGH

Key Information:

Vendor

NanoMQ

Status
NanoMQ
Vendor
CVE Published:
11 March 2026

What is CVE-2026-21888?

The NanoMQ MQTT Broker is an edge messaging platform that has an out-of-bounds read vulnerability due to improper handling of MQTT v5 variable byte integer parsing. Specifically, the function get_var_integer() permits 5-byte varints without adequate bounds checks, potentially leading to unintended memory access and application crashes. This vulnerability primarily affects versions 0.24.6 and earlier, creating significant security risks for applications utilizing these versions. Users are encouraged to review their implementations and upgrade to secure versions to mitigate potential exploits.

Affected Version(s)

nanomq <= 0.24.6

References

https://github.com/nanomq/nanomq/security/advisories/GHSA...
x_refsource_CONFIRM
https://github.com/nanomq/nanomq/issues/2192
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CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.