Client certificate bypass over HTTP/3 in OpenLiteSpeed
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- High
- Attack requirements
- Present
- Impact type
- Spoofing
- Confidentiality · integrity · availability
- High · None · None
- Fix status
- No fix listed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-295.
Summary
OpenLiteSpeed through 1.9.4 contains an authentication bypass. An improper certificate validation flaw (CWE-295) in its HTTP/3 handling lets unauthenticated remote attackers bypass virtual host client certificate requirements. The QuicStream class inherits a verifyContext() implementation that always returns true, so a request presenting the SNI of a non-mTLS host with a protected Host header reaches protected content.
Written with Claude Haiku 5.5 from the sources below · 2026-11-05
Description from the CNA
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| litespeedtech | openlitespeed | up to 1.9.4 | — | No fix listed | CNA |
- openlitespeed Vendorlitespeedtech Affected up to 1.9.4 Fixed in — No fix listed CNA
Remediation
The sources list no fixed version for OpenLiteSpeed.
Written with Claude Haiku 5.5 from the sources below · 2026-11-05
Timeline
- 2026-10-30 Threatist record created from CVE-2026-119559
- 2026-10-30 Alias added: GHSA-75rw-wm76-93p4
- 2026-11-01 Priority changed: MEDIUM → LOW
- 2026-11-05 CISA SSVC decision points changed
- 2026-11-05 Priority changed: LOW → HIGH
References
Other 4
- https://github.com/litespeedtech/openlitespeed/blob/v1.9.4/src/http/httpsession.cpp#L1665-L1672
- https://github.com/litespeedtech/openlitespeed/blob/v1.9.4/src/sslpp/hiocrypto.h#L49-L50
- https://github.com/litespeedtech/openlitespeed/blob/v1.9.4/src/quic/quicstream.h#L33-L37
- https://github.com/litespeedtech/openlitespeed
More litespeedtech vulnerabilities
- TI-2026-35606 LiteSpeed User-End cPanel Plugin before 2.4.5 allows privilege escalation (possibly to… KEVCVSS 4.0CRITICAL 10.0
- TI-2026-39296 LiteSpeed cPanel plugin before 2.4.8 (as distributed in LiteSpeed WHM PlugIn before… KEVCVSS 3.1HIGH 8.5
- TI-2024-29589 WordPress LiteSpeed Cache plugin < 6.5.0.1 - Unauthenticated Account Takeover via Cookie Leak vulnerability CVSS 3.1CRITICAL 9.8
- TI-2024-18601 WordPress LiteSpeed Cache plugin <= 6.3.0.1 - Unauthenticated Privilege Escalation vulnerability CVSS 3.1CRITICAL 9.8
- TI-2022-00030 Authenticated Remote Code Execution in OpenLiteSpeed Web Server CVSS 3.1HIGH 8.8
- TI-2023-20892 WordPress LiteSpeed Cache plugin <= 5.7 - Unauthenticated Site Wide Stored XSS vulnerability CVSS 3.1HIGH 8.3
Sources
- CVE-2026-119559 · CVE Program
- CVE-2026-119559 · NVD
- FIRST EPSS
- GHSA-75rw-wm76-93p4 · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences