DEBIAN-CVE-2026-75596

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Source
https://security-tracker.debian.org/tracker/CVE-2026-75596
Import Source
https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-75596.json
JSON Data
https://api.osv.dev/v1/vulns/DEBIAN-CVE-2026-75596
Upstream
Published
2026-08-19T21:17:37.740Z
Modified
2026-08-21T08:47:28.300733623Z
Severity
  • 8.7 (High) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/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 Calculator
Summary
[none]
Details

Netty is an asynchronous, event-driven network application framework. Prior to 4.1.137.Final and 4.2.17.Final, the default io.netty.handler.ssl.SniHandler constructors use the pre-handshake ClientHello aggregation path in handler/src/main/java/io/netty/handler/ssl/SslClientHelloHandler.java at io.netty.handler.ssl.SslClientHelloHandler#decode, where handshakeBuffer.clear() and writeBytes() recopy all previously received body bytes for every additional TLS record. An unauthenticated remote peer can advertise a large ClientHello and deliver its body in thousands of tiny records, causing quadratic CPU work on the event loop before the TLS handshake completes and degrading TLS handling for other clients. This issue is fixed in versions 4.1.137.Final and 4.2.17.Final.

References

Affected packages

Debian:11 / netty

Package

Name
netty
Purl
pkg:deb/debian/netty?arch=source&distro=bullseye

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

1:4.*
1:4.1.48-4
1:4.1.48-4+deb11u1
1:4.1.48-4+deb11u2
1:4.1.48-4+deb11u3
1:4.1.48-5
1:4.1.48-6
1:4.1.48-7
1:4.1.48-8
1:4.1.48-9
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

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-75596.json"

Debian:12 / netty

Package

Name
netty
Purl
pkg:deb/debian/netty?arch=source&distro=bookworm

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

1:4.*
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
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

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-75596.json"

Debian:13 / netty

Package

Name
netty
Purl
pkg:deb/debian/netty?arch=source&distro=trixie

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

1:4.*
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

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-75596.json"

Debian:14 / netty

Package

Name
netty
Purl
pkg:deb/debian/netty?arch=source&distro=forky

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

1:4.*
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

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-75596.json"