CVE-2026-100655

Netty before 4.1.138.Final Denial of Service via SpdySessionHandler

Published: Sep 26, 2026Updated: Sep 26, 2026 Sources: CVE List NVDCWE-770

7.5HIGH

Description

Netty (io.netty:netty-codec-http) versions up to and including 4.1.137.Final and from 4.2.0.Final through 4.2.17.Final accept an unlimited number of concurrent remote-initiated SPDY streams: SpdySessionHandler defaults localConcurrentStreams to Integer.MAX_VALUE and exposes no API to change it. A remote peer that opens a SPDY connection and sends millions of SYN_STREAM frames with FLAG_FIN=0 causes the server to allocate unbounded heap and direct memory, eventually triggering a JVM OutOfMemoryError and crashing the service. Fixed in 4.1.138.Final and 4.2.18.Final.

No summary for this CVE yet.

CVSS Vector Breakdown

Exploitability

AV:NAttack Vector

Network

AC:LAttack Complexity

Low

PR:NPrivileges Required

None

UI:NUser Interaction

None

Scope

S:UScope

Unchanged

Impact

C:NConfidentiality

None

I:NIntegrity

None

A:HAvailability

High

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Weaknesses

CWE-770

Affected Products

netty

oss-projectaka io.netty:netty, netty-incubator-codec-ohttp

nettyLibraryLibrary

OSS Libraries / generic-library

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

1 technique

Impact

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References

https://github.com/netty/netty/security/advisories/GHSA-rmcw-9fcq-wjq7

github.com

https://www.vulncheck.com/advisories/netty-before-4.1.138-final-denial-of-service-via-spdysessionhandler

vulncheck.com

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