{"id":"CVE-2026-119559","kind":"vulnerability","aliases":["CVE-2026-119559"],"related":[],"title":"OpenLiteSpeed: HTTP/3 lets attackers skip client certificate checks on virtual hosts","description":"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.","summary":"OpenLiteSpeed through 1.9.4 accepts HTTP/3 connections without enforcing a virtual host's client certificate requirement, because a certificate verification routine always returns true. An unauthenticated remote attacker can send a non-mTLS host's SNI with a protected Host header and reach content meant to require a client certificate.","severity":"high","cvss":8.2,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["http3","mtls","openlitespeed","runtime","self-hosted"],"not_affected_if":["http3-disabled","no-mtls-vhosts"],"how_to_check":"- Check the installed OpenLiteSpeed version against the `1.9.4` range stated in the advisory.\n- Look for virtual hosts that require client certificates (mTLS) and confirm whether HTTP/3 (QUIC) is enabled on the listener serving them.","fix":"- Fixed version: unknown; the sources do not name one.","status":"open","published_at":"2026-10-30T12:16:43+00:00","first_seen_at":"2026-10-30T12:30:26+00:00","triaged_at":"2026-10-30T12:32:11+00:00","updated_at":"2026-10-30T12:32:11+00:00","category":"runtime","confidence":0.6,"triage":{"at":"2026-10-30T12:32:11Z","model":"claude-haiku-5-5","output":{"fix":"- Fixed version: unknown; the sources do not name one.","reach":"internet","title":"OpenLiteSpeed: HTTP/3 lets attackers skip client certificate checks on virtual hosts","impact":"medium","summary":"OpenLiteSpeed through 1.9.4 accepts HTTP/3 connections without enforcing a virtual host's client certificate requirement, because a certificate verification routine always returns true. An unauthenticated remote attacker can send a non-mTLS host's SNI with a protected Host header and reach content meant to require a client certificate.","audience":"businesses","category":"runtime","nicknames":[],"who_cares":["openlitespeed","http3","mtls","self-hosted"],"confidence":0.6,"fix_status":"unknown","needs_auth":"no","worst_case":"Unauthenticated attackers reach content behind client certificate requirements","analyst_note":"Confirm the fixed version and any vendor advisory; the NVD entry alone gives no fix or check details.","how_to_check":"- Check the installed OpenLiteSpeed version against the `1.9.4` range stated in the advisory.\n- Look for virtual hosts that require client certificates (mTLS) and confirm whether HTTP/3 (QUIC) is enabled on the listener serving them.\n- unknown for a specific command; the sources do not give one.","plain_action":"","needs_analyst":true,"not_affected_if":["no-mtls-vhosts","http3-disabled"],"who_is_affected":"Exposure requires OpenLiteSpeed through 1.9.4 serving HTTP/3 with at least one virtual host protected by client certificate requirements. Servers that do not use mTLS on virtual hosts, or that do not serve HTTP/3, are not described as affected by the sources.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"unknown"},"cost_usd":0.000741,"input_tokens":4155,"output_tokens":652,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-119559':14A,17A '-2026':13A,16A '1.9.4':27B,77C 'accept':28B 'access':123C 'allow':84C 'alway':45B,104C 'attack':4A,51B,87C,107C 'authent':80C 'bypass':81C 'certif':7A,38B,42B,74B,93C 'check':8A 'client':6A,37B,73B,92C 'connect':30B 'contain':78C 'content':68B,125C 'cve':12A,15A 'enforc':32B 'evad':89C 'header':65B,121C 'host':11A,24B,35B,58B,64B,91C,114C,120C 'http/3':2A,29B,96C 'http3':18B 'implement':102C 'inherit':99C 'let':3A 'meant':69B 'mtls':19B,57B,113C 'non':56B,112C 'non-mtl':55B,111C 'openlitespe':1A,20B,25B,75C 'present':109C 'protect':63B,119C,124C 'quicstream':98C 'reach':67B 'remot':50B,86C 'requir':39B,71B,94C 'return':46B,105C 'routin':44B 'runtim':21B 'self':23B 'self-host':22B 'send':53B 'skip':5A 'sni':60B,116C 'true':47B,106C 'unauthent':49B,85C 'verif':43B 'verifycontext':101C 'virtual':10A,34B,90C 'vulner':82C 'without':31B","nicknames":[],"mitigations":[],"who_affected":"Exposure requires OpenLiteSpeed through 1.9.4 serving HTTP/3 with at least one virtual host protected by client certificate requirements. Servers that do not use mTLS on virtual hosts, or that do not serve HTTP/3, are not described as affected by the sources.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"unknown","audience":"businesses","plain_action":null,"first_public_at":"2026-10-30T12:16:43+00:00","kev":null,"cvss_vector":"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","cvss_by":"disclosure@vulncheck.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-119559","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-119559","severity":null,"published_at":"2026-10-30T12:16:43+00:00","modified_at":"2026-10-30T12:16:43+00:00","first_seen_at":"2026-10-30T12:30:26+00:00","fetched_at":"2026-10-30T12:30:26+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}