CVE-2026-19773
Publication date 15 September 2026
Last updated 7 October 2026
Ubuntu priority
Description
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.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| libwebsockets | 26.04 LTS resolute |
Fixed 4.3.5-3ubuntu1.2+esm1
|
| 24.04 LTS noble |
Fixed 4.3.3-1.1ubuntu0.1~esm3
|
|
| 22.04 LTS jammy |
Fixed 4.0.20-2ubuntu1.1+esm2
|
|
| 20.04 LTS focal |
Fixed 3.2.1-3ubuntu0.1~esm3
|
|
| 18.04 LTS bionic |
Fixed 2.0.3-3ubuntu0.1~esm1
|
|
| 16.04 LTS xenial |
Fixed 1.7.1-1ubuntu0.1~esm1
|
Get expanded security coverage with Ubuntu Pro
Reduce your average CVE exposure time from 98 days to 1 day with expanded CVE patching, ten-years security maintenance and optional support for the full stack of open-source applications. Free for personal use.
Get Ubuntu Pro 30-day free trialSeverity score breakdown
CVSS version: CVSS v3.0
Base score
9.8 · Critical
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
Related Ubuntu Security Notices (USN)
- USN-8893-1
- Libwebsockets vulnerabilities
- 7 October 2026