Threat intelligence dashboard
CVE-2026-19773critical

libwebsockets HTTP/2 HPACK Path Header Parsing Out-Of-Bounds Write Remote Code Execution Vulnerability

libwebsockets HTTP/2 HPACK Path Header Parsing 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 parsing of HTTP/2 HPACK path header. 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-31036.

Risk score

9.8

CVSS 3.0

Vendor
libwebsockets
Product
libwebsockets
CWE
CWE-787
Published
Sep 15, 2026
Updated
Sep 16, 2026
CISA KEV
Not flagged

Affected products and versions

libwebsockets

libwebsockets

Version / rangeStatusType
b4b5aed3903eaff09cd76a410f69bbe5dff66f8eaffected

Technical metrics

9.8

CVSS 3.0

Severity
critical
Source
zdi
Vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H