CVE-2026-34608CWE-125CWE-457

nanomq: Heap-Buffer-Overflow in webhook_inproc.c via cJSON_Parse OOB Read

Medium · published April 2, 2026

CVSS v3.1
4.9
EPSS
1%
Percentile
46.0
In the wild
Unconfirmed
What it is

NanoMQ MQTT Broker (NanoMQ) is an all-around Edge Messaging Platform. Prior to version 0.24.10, in NanoMQ's webhook_inproc.c, the hook_work_cb() function processes nng messages by parsing the message body with cJSON_Parse(body). The body is obtained from nng_msg_body(msg), which is a binary buffer without a guaranteed null terminator. This leads to an out-of-bounds read (OOB read) as cJSON_Parse reads until it finds a \0, potentially accessing memory beyond the allocated buffer (e.g., nng_msg metadata or adjacent heap/stack). The issue is often masked by nng's allocation padding (extra 32 bytes of zeros for non-power-of-two sizes <1024 or non-aligned). The overflow is reliably triggered when the JSON payload length is a power-of-two >=1024 (no padding added). This issue has been patched in version 0.24.10.

The record
Technical detail
CVSS v3.1
4.9 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
CVSS v4.0
Not supplied
EPSS
0.00563 · 46.0th percentile
Weaknesses
CWE-125 · Out-of-bounds Read; CWE-457 · Use of Uninitialized Variable
Published
2026-04-02T17:52Z
EPSS history
Timeline
  • 02 APR 17:52Z
    nanomq: Heap-Buffer-Overflow in webhook_inproc.c via cJSON_Parse OOB Read
    cvelistv5