{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-75595", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-08-17T23:49:03.449Z", "datePublished": "2026-08-19T21:00:27.627Z", "dateUpdated": "2026-08-19T21:00:27.627Z"}, "containers": {"cna": {"title": "Netty: SNI Routing Bypass via Fragmented TLS ClientHello Causing Fallback to Default SslContext", "problemTypes": [{"descriptions": [{"cweId": "CWE-754", "lang": "en", "description": "CWE-754: Improper Check for Unusual or Exceptional Conditions", "type": "CWE"}]}], "metrics": [{"cvssV4_0": {"attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "baseScore": 9.1, "baseSeverity": "CRITICAL", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N", "version": "4.0"}}], "references": [{"name": "https://github.com/netty/netty/security/advisories/GHSA-c4c3-7fpv-j4q5", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/netty/netty/security/advisories/GHSA-c4c3-7fpv-j4q5"}, {"name": "https://github.com/netty/netty/pull/17213", "tags": ["x_refsource_MISC"], "url": "https://github.com/netty/netty/pull/17213"}, {"name": "https://github.com/netty/netty/pull/17217", "tags": ["x_refsource_MISC"], "url": "https://github.com/netty/netty/pull/17217"}, {"name": "https://github.com/netty/netty/commit/1b5abc6443b63726c72cdd285af2feb7ddbb8ff7", "tags": ["x_refsource_MISC"], "url": "https://github.com/netty/netty/commit/1b5abc6443b63726c72cdd285af2feb7ddbb8ff7"}, {"name": "https://github.com/netty/netty/commit/9e0519239108a69b7e9bbc5e9182ee139a0d7961", "tags": ["x_refsource_MISC"], "url": "https://github.com/netty/netty/commit/9e0519239108a69b7e9bbc5e9182ee139a0d7961"}, {"name": "https://github.com/netty/netty/releases/tag/netty-4.1.137.Final", "tags": ["x_refsource_MISC"], "url": "https://github.com/netty/netty/releases/tag/netty-4.1.137.Final"}, {"name": "https://github.com/netty/netty/releases/tag/netty-4.2.17.Final", "tags": ["x_refsource_MISC"], "url": "https://github.com/netty/netty/releases/tag/netty-4.2.17.Final"}], "affected": [{"vendor": "netty", "product": "netty", "versions": [{"version": "< 4.1.137.Final", "status": "affected"}, {"version": ">= 4.2.0.Final, < 4.2.17.Final", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-08-19T21:00:27.627Z"}, "descriptions": [{"lang": "en", "value": "Netty is an asynchronous, event-driven network application framework. Prior to 4.1.137.Fina and 4.2.17.Final, io.netty.handler.ssl.SslClientHelloHandler#decode checks the wrong offset before reading the four-byte TLS handshake header, so a ClientHello whose handshake header spans records can cause an IndexOutOfBoundsException and invoke select(ctx, null). This selects the default SslContext instead of the SNI-specific context. In deployments where per-SNI clientAuth=REQUIRE is the sole mutual TLS gate, the default SslContext uses clientAuth=NONE or clientAuth=OPTIONAL, and no application-layer certificate verification exists, an unauthenticated remote attacker can bypass the protected route's mutual TLS requirement. This issue is fixed in versions 4.1.137.Final and 4.2.17.Final."}], "source": {"advisory": "GHSA-c4c3-7fpv-j4q5", "discovery": "UNKNOWN"}}}}

{}

{"affected": [{"affectedData": [{"product": "netty", "vendor": "netty", "versions": [{"status": "affected", "version": "< 4.1.137.Final"}, {"status": "affected", "version": ">= 4.2.0.Final, < 4.2.17.Final"}]}], "source": "security-advisories@github.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Netty is an asynchronous, event-driven network application framework. Prior to 4.1.137.Fina and 4.2.17.Final, io.netty.handler.ssl.SslClientHelloHandler#decode checks the wrong offset before reading the four-byte TLS handshake header, so a ClientHello whose handshake header spans records can cause an IndexOutOfBoundsException and invoke select(ctx, null). This selects the default SslContext instead of the SNI-specific context. In deployments where per-SNI clientAuth=REQUIRE is the sole mutual TLS gate, the default SslContext uses clientAuth=NONE or clientAuth=OPTIONAL, and no application-layer certificate verification exists, an unauthenticated remote attacker can bypass the protected route's mutual TLS requirement. This issue is fixed in versions 4.1.137.Final and 4.2.17.Final."}], "id": "CVE-2026-75595", "lastModified": "2026-08-19T21:17:37.563", "metrics": {"cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 9.1, "baseSeverity": "CRITICAL", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/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", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "security-advisories@github.com", "type": "Secondary"}]}, "published": "2026-08-19T21:17:37.563", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/netty/netty/commit/1b5abc6443b63726c72cdd285af2feb7ddbb8ff7"}, {"source": "security-advisories@github.com", "url": "https://github.com/netty/netty/commit/9e0519239108a69b7e9bbc5e9182ee139a0d7961"}, {"source": "security-advisories@github.com", "url": "https://github.com/netty/netty/pull/17213"}, {"source": "security-advisories@github.com", "url": "https://github.com/netty/netty/pull/17217"}, {"source": "security-advisories@github.com", "url": "https://github.com/netty/netty/releases/tag/netty-4.1.137.Final"}, {"source": "security-advisories@github.com", "url": "https://github.com/netty/netty/releases/tag/netty-4.2.17.Final"}, {"source": "security-advisories@github.com", "url": "https://github.com/netty/netty/security/advisories/GHSA-c4c3-7fpv-j4q5"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-754"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{}

{}