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CVE Record

CVE-2026-42578: Netty: HTTP Header Injection via HttpProxyHandler Disabled Validation

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Netty's HttpProxyHandler constructs HTTP CONNECT requests with header validation explicitly disabled. The newInitialMessage() method creates headers using DefaultHttpHeadersFactory.headersFactory().withValidation(false), then adds user-provided outboundHeaders without any CRLF validation. This allows an attacker who can influence the outbound headers to inject arbitrary HTTP headers into the CONNECT request sent to the proxy server. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

HighCVSS 7.5Not KEV-listedUpdated
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Potential ATT&CK relevance

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ATT&CK lookup starting points

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cwe · low confidence lookup

CWE-113: Exact CWE lookup

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CWE-93: Exact CWE lookup

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CVE-2026-42578 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

2CVSS vectors
5Timeline events
2ADP providers
21Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: pocAutomatable: noTechnical Impact: partial

CVSS vector scores

2 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N3.93.6redhat-SADP
2.9CVSS 4.0LowCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P——GitHub_M

Vulnerability scoring details

Base CVSS 4.0 score

2.9Low
CVSS 4.0 vector shape for CVE-2026-42578Attack VectorAttack ComplexityAttack RequirementsPrivileges RequiredUser InteractionVS ConfidentialityVS IntegrityVS AvailabilitySS ConfidentialitySS IntegritySS Availability

Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Attack Requirements
NonePresent
Privileges Required
NoneLowHigh
User Interaction
NonePassiveActive
VS Confidentiality
HighLowNone
VS Integrity
HighLowNone
VS Availability
HighLowNone
SS Confidentiality
HighLowNone
SS Integrity
HighLowNone
SS Availability
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. ADP timelineredhat-SADP

    Made public.

  3. CVE publishedCVE Program

    The CVE record was published.

  4. ADP timelineredhat-SADP

    Reported to Red Hat.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
redhat-SADPnetty: io.netty/netty-handler-proxy: Netty: HTTP Header Injection via HttpProxyHandler Disabled Validation
other:Red Hat severity ratingcvssV3_1
  • 2026-05-13T19:02:00.826Z: Reported to Red Hat.
  • 2026-05-13T17:57:43.538Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
nettynetty>= 4.2.0.Alpha1, < 4.2.13.Final, < 4.1.133.FinalListed
Weakness

CWE details

CWE-113CWE-93

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-113 · source CWE mapping

Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')

Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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CWE-93 · source CWE mapping

Improper Neutralization of CRLF Sequences ('CRLF Injection')

Improper Neutralization of CRLF Sequences ('CRLF Injection') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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