CVE catalog
CVE-2026-75595
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 t
- Severity
- Critical · CVSS 9.1
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 - Published
- Updated
- Source
- [NVD] · [CVE record]
- EPSS
- 0.32% · Oct 25, 2026
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.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | netty | sid | 1:4.1.48-16 | vulnerable |
| Debian | netty | forky | 1:4.1.48-16 | vulnerable |
| Debian | netty | trixie | 1:4.1.48-10+deb13u1 | vulnerable |
| Debian | netty | trixie-security | 1:4.1.48-10+deb13u1 | vulnerable |
| Debian | netty | bookworm | 1:4.1.48-7+deb12u2 | vulnerable |
| Debian | netty | bookworm-security | 1:4.1.48-7+deb12u2 | vulnerable |
| Maven | io.netty:netty-handler | Not reported | 4.1.137.Final | fixed |
| Cpe | netty | Not reported | 4.2.17 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | netty | source | sid | (unfixed) | not yet assigned | Not reported | [1145017] |
| Debian | netty | source | forky | (unfixed) | not yet assigned | Not reported | [1145017] |
| Debian | netty | source | trixie | (unfixed) | not yet assigned | Not reported | [1145017] |
| Debian | netty | source | bookworm | (unfixed) | not yet assigned | Not reported | [1145017] |
| Maven | io.netty:netty-handler | maven | Not reported | 4.1.137.Final | Not reported | GHSA-C4C3-7FPV-J4Q5 | Not reported |
| Cpe | netty | cpe | Not reported | 4.2.17 | Not reported | NVD-CVE-2026-75595 | Not reported |
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [libnetty-java]Affected
Source package: [netty]
Details (4)
1:4.1.48-7+deb12u2· all · bookwormAffected
nvd · netty · debian · bookworm; nvd · netty · debian · 12
1:4.1.48-7+deb12u2· all · bookwormAffected
nvd · netty · debian · bookworm; nvd · netty · debian · 12
1:4.1.48-7+deb12u2· all · bookworm-securityAffected
nvd · netty · debian · bookworm; nvd · netty · debian · 12
1:4.1.48-7+deb12u2· all · bookworm-securityAffected
nvd · netty · debian · bookworm; nvd · netty · debian · 12
[Debian 13 (Trixie)]
- [libnetty-java]Affected
Source package: [netty]
Details (4)
1:4.1.48-10+deb13u1· all · trixieAffected
nvd · netty · debian · 13
1:4.1.48-10+deb13u1· all · trixieAffected
nvd · netty · debian · 13
1:4.1.48-10+deb13u1· all · trixie-securityAffected
nvd · netty · debian · 13
1:4.1.48-10+deb13u1· all · trixie-securityAffected
nvd · netty · debian · 13
Observed:
References
- [https://ftp.suse.com/pub/projects/security/csaf/opensuse-su-2026_11882-1.json]
- [https://github.com/advisories/GHSA-c4c3-7fpv-j4q5]
- [https://github.com/netty/netty/commit/1b5abc6443b63726c72cdd285af2feb7ddbb8ff7]
- [https://github.com/netty/netty/commit/9e0519239108a69b7e9bbc5e9182ee139a0d7961]
- [https://github.com/netty/netty/pull/17213]
- [https://github.com/netty/netty/pull/17217]
- [https://github.com/netty/netty/releases/tag/netty-4.1.137.Final]
- [https://github.com/netty/netty/releases/tag/netty-4.2.17.Final]
- [https://github.com/netty/netty/security/advisories/GHSA-c4c3-7fpv-j4q5]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-75595]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-75595]
- [https://security-tracker.debian.org/tracker/CVE-2026-75595]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-75595.json]
- [https://wid.cert-bund.de/.well-known/csaf/white/2026/wid-sec-w-2026-3376.json]
[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [GitHub Advisory Database] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]