CVE-2026-59898

Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.136.Final and 4.2.16.Final, ab attacker can force WebSocket upgrade via the lax V07 (or V08) handshaker by sending `Sec-WebSocket-Version: 7` and omitting `Connection: Upgrade` / `Upgrade: websocket` headers, completing a protocol switch that a proxy would not recognize as an Upgrade request and enabling HTTP request smuggling / protocol-confusion attacks. This issue has been fixed in versions 4.1.136.Final and 4.2.16.Final.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/netty/netty/releases/tag/netty-4.1.136.Final	Release Notes
https://github.com/netty/netty/releases/tag/netty-4.2.16.Final	Release Notes
https://github.com/netty/netty/security/advisories/GHSA-4mp9-239f-g9hg	Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:netty:netty::::::::
	cpe:2.3:a:netty:netty::::::::

History

06 Aug 2026, 20:35

Type	Values Removed	Values Added
First Time		Netty netty Netty
CPE		cpe:2.3:a:netty:netty::::::::
References	~~() https://github.com/netty/netty/releases/tag/netty-4.1.136.Final -~~	() https://github.com/netty/netty/releases/tag/netty-4.1.136.Final - Release Notes
References	~~() https://github.com/netty/netty/releases/tag/netty-4.2.16.Final -~~	() https://github.com/netty/netty/releases/tag/netty-4.2.16.Final - Release Notes
References	~~() https://github.com/netty/netty/security/advisories/GHSA-4mp9-239f-g9hg -~~	() https://github.com/netty/netty/security/advisories/GHSA-4mp9-239f-g9hg - Vendor Advisory
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 7.5

29 Jul 2026, 19:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-07-29 19:16

Updated : 2026-08-06 20:35

NVD link : CVE-2026-59898

Mitre link : CVE-2026-59898

CVE.ORG link : CVE-2026-59898

JSON object : View

Products Affected

netty

netty

CWE

CWE-444

Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

{"id": "CVE-2026-59898", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-59898", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-07-30T13:55:09.323754Z"}}], "cvssMetricV31": [{"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 3.9}], "cvssMetricV40": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 6.3, "Automatable": "NOT_DEFINED", "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/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", "exploitMaturity": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "userInteraction": "NONE", "attackComplexity": "HIGH", "attackRequirements": "NONE", "privilegesRequired": "NONE", "subIntegrityImpact": "LOW", "vulnIntegrityImpact": "NONE", "integrityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "availabilityRequirement": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "subConfidentialityImpact": "LOW", "vulnConfidentialityImpact": "NONE", "confidentialityRequirement": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED"}}]}, "affected": [{"source": "security-advisories@github.com", "affectedData": [{"vendor": "netty", "product": "netty", "versions": [{"status": "affected", "version": ">=4.2.0.Final, < 4.2.16.Final"}, {"status": "affected", "version": "< 4.1.136.Final"}]}]}], "published": "2026-07-29T19:16:48.740", "references": [{"url": "https://github.com/netty/netty/releases/tag/netty-4.1.136.Final", "tags": ["Release Notes"], "source": "security-advisories@github.com"}, {"url": "https://github.com/netty/netty/releases/tag/netty-4.2.16.Final", "tags": ["Release Notes"], "source": "security-advisories@github.com"}, {"url": "https://github.com/netty/netty/security/advisories/GHSA-4mp9-239f-g9hg", "tags": ["Vendor Advisory"], "source": "security-advisories@github.com"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-444"}]}], "descriptions": [{"lang": "en", "value": "Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.136.Final and 4.2.16.Final, ab attacker can force WebSocket upgrade via the lax V07 (or V08) handshaker by sending `Sec-WebSocket-Version: 7` and omitting `Connection: Upgrade` / `Upgrade: websocket` headers, completing a protocol switch that a proxy would not recognize as an Upgrade request and enabling HTTP request smuggling / protocol-confusion attacks. This issue has been fixed in versions 4.1.136.Final and 4.2.16.Final."}], "lastModified": "2026-08-06T20:35:23.360", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "3A15093F-C6A7-4FCF-81BA-939CD522D1DD", "versionEndExcluding": "4.1.136"}, {"criteria": "cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "4DE4BC35-4405-49B5-A2A8-A700C7F63C8B", "versionEndExcluding": "4.2.16", "versionStartIncluding": "4.2.0"}], "operator": "OR"}]}], "sourceIdentifier": "security-advisories@github.com"}