Vulnerability · Published Jun 14, 2026 · Assigned by TuranSec

CVE-2026-54412MQTT-C Heap Out-of-Bounds Read and Integer Underflow in mqtt_unpack_publish_response()

High 8.2

In plain English

A high-severity out-of-bounds read in MQTT-C from LiamBindle. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 37% of all known vulnerabilities).

Severity (CVSS 3.1)8.2High

Exploit odds (30 days)0.4%top 62.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

LiamBindle MQTT-C versions prior to 1.1.7 contain a heap-based out-of-bounds read and integer underflow in the mqtt_unpack_publish_response() function in src/mqtt.c. A remote unauthenticated attacker controlling an MQTT broker, or capable of injecting MQTT traffic into an unencrypted session, can crash a subscribed MQTT-C client and potentially disclose adjacent heap memory by sending a single crafted PUBLISH packet.

Affected products (as reported)

Vendor	Product	Versions
LiamBindle	MQTT-C	0 – before 1.1.7

Weakness: CWE-125, CWE-191 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H

References

LiamBindle/MQTT-C upstream repository product
Vulnerable mqtt_unpack_publish_response() in src/mqtt.c (v1.1.6) product
Fix out-of-bounds read and integer underflow in PUBLISH parsing patch
MQTT-C v1.1.7 release release-notes, patch
CWE-125: Out-of-bounds Read technical-description
CWE-191: Integer Underflow (Wrap or Wraparound) technical-description