---
id: CVE-2026-119559
title: OpenLiteSpeed through 1.9.4 mTLS Bypass via HTTP/3 SNI and Host Mismatch
summary: >-
  OpenLiteSpeed through 1.9.4 contains an authentication bypass vulnerability
  that allows unauthenticated remote attackers to evade virtual host client
  certificate requirements over HTTP/3. Because QuicStream inherits a
  verifyContext() imp…
severity: medium
cvss: 5.9
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N'
cvssSource: cna
cwe:
  - CWE-295
vendor: litespeedtech
product: openlitespeed
affected:
  - openlitespeed <= 1.9.4
published: '2026-10-30'
updated: '2026-10-30'
sourceUpdated: '2026-10-30T11:31:08.276Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-119559'
references:
  - url: >-
      https://github.com/litespeedtech/openlitespeed/blob/v1.9.4/src/http/httpsession.cpp#L1665-L1672
  - url: >-
      https://github.com/litespeedtech/openlitespeed/blob/v1.9.4/src/sslpp/hiocrypto.h#L49-L50
  - url: >-
      https://github.com/litespeedtech/openlitespeed/blob/v1.9.4/src/quic/quicstream.h#L33-L37
  - url: 'https://abraxaslabs.tech/research/openlitespeed-h3-mtls-verifycontext'
  - url: 'https://github.com/litespeedtech/openlitespeed'
  - url: >-
      https://www.vulncheck.com/advisories/openlitespeed-through-1.9.4-mtls-bypass-via-http-3-sni-and-host-mismatch
    label: >-
      VulnCheck Advisory: OpenLiteSpeed through 1.9.4 mTLS Bypass via HTTP/3 SNI
      and Host Mismatch
tags:
  - cve.org
epss: 0.00289
epssPercentile: 0.21538
ingestedAt: '2026-11-03T11:43:15.774Z'
---

## Overview

OpenLiteSpeed through 1.9.4 contains an authentication bypass vulnerability that allows unauthenticated remote attackers to evade virtual host client certificate requirements over HTTP/3. Because QuicStream inherits a verifyContext() implementation that always returns true, attackers can present a non-mTLS host's SNI with a protected Host header to access protected content.

## Affected

- `openlitespeed <= 1.9.4`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.