High
netty — security advisory
Netty (io.netty:netty-handler) versions from 4.2.0.Final through 4.2.16.Final and versions through 4.1.136.Final disable TLS hostname verification on the SslProvider.OPENSSL client path when a plain (non-extended) X509TrustManager is used and Unsafe-based trust-manager wrapping is unavailable (Java 25+). In this configuration the OpenSSL client does not perform hostname verification, allowing a man-in-the-middle attacker to present a certificate issued for a different hostname that is accepted without validation. Fixed in 4.2.17.Final and 4.1.137.Final.
- Products
- netty
- Affected versions
- 1:4.1.48-10, 1:4.1.48-10+deb13u1, 1:4.1.48-11, 1:4.1.48-12, 1:4.1.48-13, 1:4.1.48-14, 1:4.1.48-15, 1:4.1.48-16, 1:4.1.48-7, 1:4.1.48-7+deb12u1, 1:4.1.48-7+deb12u2, 1:4.1.48-8, 1:4.1.48-9
- Fixed versions
- Not specified
- CVEs
- CVE-2026-62243
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 30 Oct 2026, 16:16 UTC · Revision 1
Source evidence
Netty (io.netty:netty-handler) versions from 4.2.0.Final through 4.2.16.Final and versions through 4.1.136.Final disable TLS hostname verification on the SslProvider.OPENSSL client path when a plain (non-extended) X509TrustManager is used and Unsafe-based trust-manager wrapping is unavailable (Java 25+). In this configuration the OpenSSL client does not perform hostname verification, allowing a man-in-the-middle attacker to present a certificate issued for a different hostname that is accepted without validation. Fixed in 4.2.17.Final and 4.1.137.Final.
osv:DEBIAN-CVE-2026-62243
netty
Fixed versions: Not specified
netty
Fixed versions: Not specified
netty
Fixed versions: Not specified
Complete source record
{
"id": "0c0df1042bc8697858318b6e211d5ac2a8e530b54bcf9a057eb5293035b06c09",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-62243",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2026-62243",
"summary": "Netty (io.netty:netty-handler) versions from 4.2.0.Final through 4.2.16.Final and versions through 4.1.136.Final disable TLS hostname verification on the SslProvider.OPENSSL client path when a plain (non-extended) X509TrustManager is used and Unsafe-based trust-manager wrapping is unavailable (Java 25+). In this configuration the OpenSSL client does not perform hostname verification, allowing a man-in-the-middle attacker to present a certificate issued for a different hostname that is accepted without validation. Fixed in 4.2.17.Final and 4.1.137.Final.",
"evidence": "osv:DEBIAN-CVE-2026-62243",
"products": [
{
"name": {
"value": "netty",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "1:4.1.48-10",
"evidence": "/affected/0/versions"
},
{
"value": "1:4.1.48-11",
"evidence": "/affected/0/versions"
},
{
"value": "1:4.1.48-12",
"evidence": "/affected/0/versions"
},
{
"value": "1:4.1.48-13",
"evidence": "/affected/0/versions"
},
{
"value": "1:4.1.48-14",
"evidence": "/affected/0/versions"
},
{
"value": "1:4.1.48-15",
"evidence": "/affected/0/versions"
},
{
"value": "1:4.1.48-16",
"evidence": "/affected/0/versions"
},
{
"value": "1:4.1.48-7",
"evidence": "/affected/0/versions"
},
{
"value": "1:4.1.48-7+deb12u1",
"evidence": "/affected/0/versions"
},
{
"value": "1:4.1.48-7+deb12u2",
"evidence": "/affected/0/versions"
},
{
"value": "1:4.1.48-8",
"evidence": "/affected/0/versions"
},
{
"value": "1:4.1.48-9",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "netty",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "1:4.1.48-10",
"evidence": "/affected/1/versions"
},
{
"value": "1:4.1.48-10+deb13u1",
"evidence": "/affected/1/versions"
},
{
"value": "1:4.1.48-11",
"evidence": "/affected/1/versions"
},
{
"value": "1:4.1.48-12",
"evidence": "/affected/1/versions"
},
{
"value": "1:4.1.48-13",
"evidence": "/affected/1/versions"
},
{
"value": "1:4.1.48-14",
"evidence": "/affected/1/versions"
},
{
"value": "1:4.1.48-15",
"evidence": "/affected/1/versions"
},
{
"value": "1:4.1.48-16",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
"value": "netty",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "1:4.1.48-10",
"evidence": "/affected/2/versions"
},
{
"value": "1:4.1.48-11",
"evidence": "/affected/2/versions"
},
{
"value": "1:4.1.48-12",
"evidence": "/affected/2/versions"
},
{
"value": "1:4.1.48-13",
"evidence": "/affected/2/versions"
},
{
"value": "1:4.1.48-14",
"evidence": "/affected/2/versions"
},
{
"value": "1:4.1.48-15",
"evidence": "/affected/2/versions"
},
{
"value": "1:4.1.48-16",
"evidence": "/affected/2/versions"
}
]
}
],
"severity": "high",
"structured": {
"id": "DEBIAN-CVE-2026-62243",
"aliases": [
"DEBIAN-CVE-2026-62243"
],
"metrics": [
{
"type": "CVSS_V4",
"score": "CVSS:4.0/AV:N/AC:L/AT:N/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"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "netty",
"purl": "pkg:deb/debian/netty?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"1:4.1.48-10",
"1:4.1.48-11",
"1:4.1.48-12",
"1:4.1.48-13",
"1:4.1.48-14",
"1:4.1.48-15",
"1:4.1.48-16",
"1:4.1.48-7",
"1:4.1.48-7+deb12u1",
"1:4.1.48-7+deb12u2",
"1:4.1.48-8",
"1:4.1.48-9"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-62243.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "netty",
"purl": "pkg:deb/debian/netty?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"1:4.1.48-10",
"1:4.1.48-10+deb13u1",
"1:4.1.48-11",
"1:4.1.48-12",
"1:4.1.48-13",
"1:4.1.48-14",
"1:4.1.48-15",
"1:4.1.48-16"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-62243.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "netty",
"purl": "pkg:deb/debian/netty?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"1:4.1.48-10",
"1:4.1.48-11",
"1:4.1.48-12",
"1:4.1.48-13",
"1:4.1.48-14",
"1:4.1.48-15",
"1:4.1.48-16"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-62243.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-15T09:47:26.697646457Z",
"provider": "osv",
"upstream": [
"CVE-2026-62243"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2026-62243"
]
},
"related_cves": [
{
"value": "CVE-2026-62243",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 327325,
"published_at": "2026-08-22T13:16:39.687+00:00"
}