CVE-2026-21888
MQTT v5 Variable Byte Integer parsing out-of-bounds: get_var_integer()
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.
INFO
Published Date :
March 11, 2026, 4:16 p.m.
Last Modified :
March 17, 2026, 7:20 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 3.1 | HIGH | MITRE-CVE |
Solution
- Update NanoMQ to a version later than 0.24.6.
- Apply vendor patches to fix integer parsing.
- Rebuild the broker without ASan if applicable.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-21888.
| URL | Resource |
|---|---|
| https://github.com/nanomq/nanomq/issues/2192 | Issue Tracking |
| https://github.com/nanomq/nanomq/security/advisories/GHSA-cggc-6m7w-j7x5 | Exploit Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-21888 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-21888
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-21888 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-21888 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Mar. 17, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:emqx:nanomq:*:*:*:*:*:*:*:* versions up to (including) 0.24.6 Added Reference Type GitHub, Inc.: https://github.com/nanomq/nanomq/issues/2192 Types: Issue Tracking Added Reference Type GitHub, Inc.: https://github.com/nanomq/nanomq/security/advisories/GHSA-cggc-6m7w-j7x5 Types: Exploit, Vendor Advisory -
New CVE Received by [email protected]
Mar. 11, 2026
Action Type Old Value New Value Added 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. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-125 Added Reference https://github.com/nanomq/nanomq/issues/2192 Added Reference https://github.com/nanomq/nanomq/security/advisories/GHSA-cggc-6m7w-j7x5