Bug 2566614 (CVE-2026-114550)

Summary:	CVE-2026-114550 libwebsockets: libwebsockets: arbitrary code execution via crafted MQTT PUBACK packets
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	ansmith, eglynn, jbritton, jjoyce, jpretori, jschluet, lhh, mburns, mgarciac, pjindal
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
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Doc Text:	A flaw was found in libwebsockets. When processing Message Queuing Telemetry Transport (MQTT) publish acknowledgment (PUBACK) packets, incoming network data is not properly validated, resulting in an out-of-bounds memory write. An unauthenticated remote attacker can exploit this vulnerability by sending specially crafted packets to execute arbitrary code in the context of the running application.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
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Description OSIDB Bzimport 2026-11-04 00:01:32 UTC

libwebsockets MQTT Protocol PUBACK Packet Handling Out-Of-Bounds Write Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of libwebsockets. Authentication is not required to exploit this vulnerability.

The specific flaw exists within the handling of PUBACK packets. The issue results from the lack of proper validation of user-supplied data, which can result in a write past the end of an allocated buffer. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-31039.