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Medium 4.9Published Apr 2, 2026

CVE-2026-34608nanomq: Heap-Buffer-Overflow in webhook_inproc.c via cJSON_Parse OOB Read

Updated under an hour ago ()

Does this affect you?

It affects nanomq and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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.

CVSS
4.9 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE)
CWE-125, CWE-457
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
GitHub_M
NVD analysis
Analyzed
Record last updated
Apr 2, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
nanomq nanomq
nanomq:nanomq (from the name)
before 0.24.10
CNA record
emqx nanomq
emqx:nanomq
before 0.24.10
NVD

References

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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