CVE-2026-119559

MEDIUM 5.9

OpenLiteSpeed through 1.9.4 mTLS Bypass via HTTP/3 SNI and Host Mismatch

CVSS Score

5.9

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-295
Vendor	litespeedtech
Product	openlitespeed
Published	Oct 30, 2026

Stay Ahead of the Next One

Get instant alerts for litespeedtech openlitespeed

Be the first to know when new medium vulnerabilities affecting litespeedtech openlitespeed are published — delivered to Slack, Telegram or Discord.

Get Free Alerts → Free · No credit card · 60 sec setup

CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Affected Versions

litespeedtech / openlitespeed

0 ≤ 1.9.4

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/litespeedtech/openlitespeed/blob/v1.9.4/src/http/httpsession.cpp#L1665-L1672 github.com: https://github.com/litespeedtech/openlitespeed/blob/v1.9.4/src/sslpp/hiocrypto.h#L49-L50 github.com: https://github.com/litespeedtech/openlitespeed/blob/v1.9.4/src/quic/quicstream.h#L33-L37 abraxaslabs.tech: https://abraxaslabs.tech/research/openlitespeed-h3-mtls-verifycontext github.com: https://github.com/litespeedtech/openlitespeed vulncheck.com: https://www.vulncheck.com/advisories/openlitespeed-through-1.9.4-mtls-bypass-via-http-3-sni-and-host-mismatch

Credits

Abraxas Labs