CVE-2026-54412
MQTT-C Heap Out-of-Bounds Read and Integer Underflow in mqtt_unpack_publish_response()
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.
Fixes and workarounds
Fix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: CNA: TuranSecFix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: CNA: TuranSecAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| MQTT-C LiamBindle https://github.com/LiamBindle/MQTT-C |
≥ 0; < 1.1.7 (affected, semver) 1.1.7 (unaffected, semver) Other versions: unknown |
CNA: TuranSec |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 4.0 / 7.8 high |
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N/E:P/AU:Y/V:D | CNA: TuranSec |
| 3.1 / 8.2 high |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H | CNA: TuranSec |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://github.com/LiamBindle/MQTT-CCNA: TuranSec · product
- https://github.com/LiamBindle/MQTT-C/blob/v1.1.6/src/mqtt.c#L1334CNA: TuranSec · product
- https://github.com/LiamBindle/MQTT-C/pull/208CNA: TuranSec · patch
- https://github.com/LiamBindle/MQTT-C/releases/tag/v1.1.7CNA: TuranSec · release-notes, patch
- https://cwe.mitre.org/data/definitions/125.htmlCNA: TuranSec · technical-description
- https://cwe.mitre.org/data/definitions/191.htmlCNA: TuranSec · technical-description
For agents and automation
Read public disclosures for free as Markdown or JSON. Compatible browsers also expose native WebMCP tools to search disclosures, read this page, and discover API access.
Use the ontology-linked Cyber API with x402 pay per request, or a Y2 Pro or Elite API key with the intel:cyber scope.
Endpoints and access details
https://api.y2.dev/api/v2/cyber/cveshttps://api.y2.dev/api/v2/cyber/cves/{cveId}
A workspace owner or admin can create a Pro or Elite API key. Send Authorization: Bearer <Y2_API_KEY> from your trusted agent runtime.
For x402, omit Authorization and read the HTTP 402 payment challenge before signing a retry. Public browser tools do not make payments.