# CVE-2026-44640: NanoMQ type confusion in QUIC dialer close path

Source: https://junglewise.ai/threats/cve-2026-44640-nanomq-type-confusion-in-quic-dialer-close-path  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-29. Updated: 2026-05-29  
License: CC BY 4.0 with a link back

CVE-2026-44640 · Severity: medium · CVSS 4.5 · Published 2026-05-29

NanoMQ is an open-source messaging platform used for communication between edge devices and cloud systems. A flaw in how the software handles secure QUIC connections can cause the system to hang or crash when a connection attempt is canceled or closed. This could allow an attacker to disrupt messaging services, leading to a denial-of-service condition that impacts real-time data operations.

Technologies: [EMQ NanoMQ](https://junglewise.ai/threats/technologies/nanomq). Vendors: [EMQ](https://junglewise.ai/threats/vendors/emq).

## Quick answers

**Is CVE-2026-44640 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-44640 being exploited in the wild.

**How severe is CVE-2026-44640?** Medium severity, with a CVSS score of 4.5, published 29 May 2026.

**Which products and versions are affected?** EMQ NanoMQ < 0.24.14.

**Is there a fix for CVE-2026-44640?** A patch was published on 2026-05-29: Version 0.24.14 released with fix Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-44640 attacked?** It is attacked with local access, in a software library.

**Am I affected by CVE-2026-44640?** Check whether you run EMQ NanoMQ at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A type confusion vulnerability exists in NanoMQ's QUIC implementation within `nng/src/supplemental/quic/msquic_dial.c`. During the dialing process, the `aio->prov_data` field is populated with a pointer of type `nni_quic_conn*`; however, during the dialer close path, the code incorrectly attempts to read this data as an `ex_quic_conn*`. This incompatible type interpretation leads to invalid memory access, resulting in a process hang or crash (Denial of Service). Exploitation requires specific timing during the connection phase and is categorized as having high complexity. The issue is resolved in version 0.24.14.

## Affected products

- EMQ NanoMQ < 0.24.14

## Timeline

- 2026-05-19: advisory: GitHub Security Advisory published
- 2026-05-29: patched: Version 0.24.14 released with fix
- 2026-05-29: disclosed: CVE-2026-44640 published to NVD

## References

- [https://github.com/nanomq/nanomq/releases/tag/0.24.14](https://github.com/nanomq/nanomq/releases/tag/0.24.14)
- [https://github.com/nanomq/nanomq/security/advisories/GHSA-9fgw-v323-jmjj](https://github.com/nanomq/nanomq/security/advisories/GHSA-9fgw-v323-jmjj)

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