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.

Attack Vector Local

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
netty netty unaffected
Version Status Constraints
0 affected < 4.1.138.Final
4.1.138.Final unaffected —
netty netty unaffected
Version Status Constraints
4.2.0.Final affected < 4.2.18.Final
4.2.18.Final unaffected —

No data.

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Project Subscriptions

Vendors Products
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Netty Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/netty/netty/security/advisories/GHSA-rmcw-9fcq-wjq7 cve-icon
https://www.vulncheck.com/advisories/netty-before-4.1.138-final-denial-of-service-via-spdysessionhandler cve-icon
History

Sat, 26 Sep 2026 13:30:00 +0000

Type Values Removed Values Added
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.
Title Netty before 4.1.138.Final Denial of Service via SpdySessionHandler
First Time appeared Netty
Netty netty
Weaknesses CWE-770
CPEs cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*
Vendors & Products Netty
Netty netty
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-09-26T13:23:23.988Z

Reserved: 2026-09-26T02:33:07.899Z

Link: CVE-2026-100655

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses