# CVE-2026-119559: OpenLiteSpeed through 1.9.4 mTLS Bypass via HTTP/3 SNI and Host Mismatch

Status: published. Published: 2026-10-30. Updated: 2026-11-05.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- litespeedtech / openlitespeed (litespeedtech/openlitespeed): ≥ 0; ≤ 1.9.4 (affected, semver). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 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; source: CNA: VulnCheck

- CVSS 3.1: 5.9 (medium); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N; source: CNA: VulnCheck

- CISA KEV: No listing in collected sources

- EPSS: 0.29% as of 2026-11-05; percentile 21.63%

- SSVC: exploitation poc; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-295

## Exploit evidence

- exploit: https://abraxaslabs.tech/research/openlitespeed-h3-mtls-verifycontext (ADP: CISA-ADP)

## References

- https://github.com/litespeedtech/openlitespeed/blob/v1.9.4/src/http/httpsession.cpp#L1665-L1672 (CNA: VulnCheck; technical-description)

- https://github.com/litespeedtech/openlitespeed/blob/v1.9.4/src/sslpp/hiocrypto.h#L49-L50 (CNA: VulnCheck; technical-description)

- https://github.com/litespeedtech/openlitespeed/blob/v1.9.4/src/quic/quicstream.h#L33-L37 (CNA: VulnCheck; technical-description)

- https://abraxaslabs.tech/research/openlitespeed-h3-mtls-verifycontext (CNA: VulnCheck; third-party-advisory)

- https://github.com/litespeedtech/openlitespeed (CNA: VulnCheck; product)

- https://www.vulncheck.com/advisories/openlitespeed-through-1.9.4-mtls-bypass-via-http-3-sni-and-host-mismatch (CNA: VulnCheck; third-party-advisory)

- https://abraxaslabs.tech/research/openlitespeed-h3-mtls-verifycontext (ADP: CISA-ADP; exploit)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-119559; retrieved 2026-11-05; source updated 2026-11-05

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-119559; retrieved 2026-11-05; source updated Not reported

Revision: c292c905ba8fcc766ae45db381f408b6ac4809a1920e919c7c84b8ddd74e3cd9

Canonical: https://y2.dev/cve/CVE-2026-119559

## Agent and API access

Public CVE pages, Markdown, and JSON are free to read without an account or API key.

- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search, filters, sort, and limit (1–100). A null cursor marks the end.

- WebMCP: search_cve_disclosures, get_cve_disclosure, get_cve_page_markdown, get_y2_cve_access. Available in compatible browsers.

- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

Collected public records only. Check source status for coverage and freshness.