CVE-2026-119559
OpenLiteSpeed through 1.9.4 mTLS Bypass via HTTP/3 SNI and Host Mismatch
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.
Fixes and workarounds
No remediation reported in collected sources.
Missing remediation information is not evidence that no patch exists.
Affected products and versions
| Product | Versions | Authority |
|---|---|---|
| openlitespeed litespeedtech litespeedtech/openlitespeed
github |
≥ 0; ≤ 1.9.4 (affected, semver)
Other versions: unaffected |
CNA: VulnCheck |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 4.0 / 8.2 high |
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N | CNA: VulnCheck |
| 3.1 / 5.9 medium |
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N | CNA: VulnCheck |
Exploit evidence
- https://abraxaslabs.tech/research/openlitespeed-h3-mtls-verifycontext
exploit · ADP: CISA-ADP
References
- https://github.com/litespeedtech/openlitespeed/blob/v1.9.4/src/http/httpsession.cpp#L1665-L1672CNA: VulnCheck · technical-description
- https://github.com/litespeedtech/openlitespeed/blob/v1.9.4/src/sslpp/hiocrypto.h#L49-L50CNA: VulnCheck · technical-description
- https://github.com/litespeedtech/openlitespeed/blob/v1.9.4/src/quic/quicstream.h#L33-L37CNA: VulnCheck · technical-description
- https://abraxaslabs.tech/research/openlitespeed-h3-mtls-verifycontextCNA: VulnCheck · third-party-advisory
- https://github.com/litespeedtech/openlitespeedCNA: VulnCheck · product
- https://www.vulncheck.com/advisories/openlitespeed-through-1.9.4-mtls-bypass-via-http-3-sni-and-host-mismatchCNA: VulnCheck · third-party-advisory
- https://abraxaslabs.tech/research/openlitespeed-h3-mtls-verifycontextADP: CISA-ADP · exploit
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