CVE-2026-21888CWE-125

MQTT v5 Variable Byte Integer parsing out-of-bounds: get_var_integer()

High · published March 11, 2026

CVSS v3.1
7.5
EPSS
0%
Percentile
23.1
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
7.5 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v4.0
Not supplied
EPSS
0.00314 · 23.1th percentile
Weakness
CWE-125 · Out-of-bounds Read
Published
2026-03-11T15:22Z
EPSS history
Timeline
  • 11 MAR 15:22Z
    MQTT v5 Variable Byte Integer parsing out-of-bounds: get_var_integer()
    cvelistv5