Is CVE-2026-21888 actively exploited?

No active exploitation of CVE-2026-21888 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-21888 be exploited remotely?

Yes. CVE-2026-21888 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-21888?

CVE-2026-21888 has a CVSS score of 7.5 (HIGH).

HOME VULNERABILITIESCVE-2026-21888

HIGH

CVE-2026-21888

CWE-125Published: March 11, 2026· Updated: Mar 17, 2026

7.5

CVSS v3.1

EPSS:0.05%probability of exploitation in 30 daysPercentile:15.9th

Official Description

NanoMQ MQTT Broker (NanoMQ) is an all-around Edge Messaging Platform. MQTT v5 Variable Byte Integer parsing out-of-bounds: get_var_integer() accepts 5-byte varints without bounds checks; reliably triggers OOB read / crash when built with ASan. This affects 0.24.6 and earlier.

NVD Source

Technical Analysis

CVE-2026-21888 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 7.5.