CVE-2026-19773 PUBLISHED

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

Assigner: zdi
Reserved: 13.08.2026 Published: 15.09.2026 Updated: 16.09.2026

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.

Metrics

CVSS Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS Score: 9.8

Product Status

Vendor libwebsockets
Product libwebsockets
Versions Default: unknown
  • Version b4b5aed3903eaff09cd76a410f69bbe5dff66f8e is affected

References

Problem Types

  • CWE-787: Out-of-bounds Write CWE