CVE-2026-78669

A malicious HTTP/2 peer can cause excessive CPU consumption in the client or server by opening a large number of streams and then sending many small SETTINGS frames containing SETTINGS_INITIAL_WINDOW_SIZE values.

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 NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://go.dev/cl/847186
https://go.dev/cl/847308
https://go.dev/issue/81742
https://groups.google.com/g/golang-announce/c/U2fTuyDJznI
https://groups.google.com/g/golang-announce/c/ZPwCyRUuGBs
https://pkg.go.dev/vuln/GO-2026-6611

Configurations

No configuration.

History

09 Oct 2026, 17:16

Type	Values Removed	Values Added
CWE		CWE-405
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 7.5

08 Oct 2026, 23:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-08 23:17

Updated : 2026-10-09 17:16

NVD link : CVE-2026-78669

Mitre link : CVE-2026-78669

CVE.ORG link : CVE-2026-78669

JSON object : View

Products Affected

No product.

CWE

CWE-405

Asymmetric Resource Consumption (Amplification)

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{"name": "ServeFile"}, {"name": "ServeFileFS"}, {"name": "ServeMux.Handle"}, {"name": "ServeMux.HandleFunc"}, {"name": "ServeMux.ServeHTTP"}, {"name": "ServeTLS"}, {"name": "Server.Close"}, {"name": "Server.ListenAndServe"}, {"name": "Server.ListenAndServeTLS"}, {"name": "Server.Serve"}, {"name": "Server.ServeTLS"}, {"name": "Server.SetKeepAlivesEnabled"}, {"name": "Server.Shutdown"}, {"name": "SetCookie"}, {"name": "Transport.CancelRequest"}, {"name": "Transport.Clone"}, {"name": "Transport.CloseIdleConnections"}, {"name": "Transport.NewClientConn"}, {"name": "Transport.RoundTrip"}, {"name": "body.Close"}, {"name": "body.Read"}, {"name": "bodyEOFSignal.Close"}, {"name": "bodyEOFSignal.Read"}, {"name": "bodyLocked.Read"}, {"name": "bufioFlushWriter.Write"}, {"name": "cancelTimerBody.Close"}, {"name": "cancelTimerBody.Read"}, {"name": "checkConnErrorWriter.Write"}, {"name": "chunkWriter.Write"}, {"name": "connReader.Read"}, {"name": "connectMethodKey.String"}, {"name": "expectContinueReader.Close"}, {"name": "expectContinueReader.Read"}, {"name": "extraHeader.Write"}, {"name": "fileHandler.ServeHTTP"}, {"name": "fileTransport.RoundTrip"}, {"name": "globalOptionsHandler.ServeHTTP"}, {"name": "gzipReader.Close"}, {"name": "gzipReader.Read"}, {"name": "http1ClientConn.Close"}, {"name": "http1ClientConn.RoundTrip"}, {"name": "http2ClientConn.Close"}, {"name": "http2ClientConn.Ping"}, {"name": "http2ClientConn.RoundTrip"}, {"name": "http2ClientConn.Shutdown"}, {"name": "http2ConnectionError.Error"}, {"name": "http2ErrCode.String"}, {"name": "http2FrameHeader.String"}, {"name": "http2FrameType.String"}, {"name": "http2FrameWriteRequest.String"}, {"name": "http2Framer.ReadFrame"}, {"name": "http2Framer.ReadFrameForHeader"}, {"name": "http2Framer.ReadFrameHeader"}, {"name": "http2Framer.WriteContinuation"}, {"name": "http2Framer.WriteData"}, {"name": "http2Framer.WriteDataPadded"}, {"name": "http2Framer.WriteGoAway"}, {"name": "http2Framer.WriteHeaders"}, {"name": "http2Framer.WritePing"}, {"name": "http2Framer.WritePriority"}, {"name": "http2Framer.WritePushPromise"}, {"name": "http2Framer.WriteRSTStream"}, {"name": "http2Framer.WriteRawFrame"}, {"name": "http2Framer.WriteSettings"}, {"name": "http2Framer.WriteSettingsAck"}, {"name": "http2Framer.WriteWindowUpdate"}, {"name": "http2GoAwayError.Error"}, {"name": "http2Server.ServeConn"}, {"name": "http2Setting.String"}, {"name": "http2SettingID.String"}, {"name": "http2SettingsFrame.ForeachSetting"}, {"name": "http2StreamError.Error"}, {"name": "http2Transport.CloseIdleConnections"}, {"name": "http2Transport.NewClientConn"}, {"name": "http2Transport.RoundTrip"}, {"name": "http2Transport.RoundTripOpt"}, {"name": "http2bufferedWriter.Flush"}, {"name": "http2bufferedWriter.Write"}, {"name": "http2bufferedWriterTimeoutWriter.Write"}, {"name": "http2chunkWriter.Write"}, {"name": "http2clientConnPool.GetClientConn"}, {"name": "http2connError.Error"}, {"name": "http2dataBuffer.Read"}, {"name": "http2duplicatePseudoHeaderError.Error"}, {"name": "http2gzipReader.Close"}, {"name": "http2gzipReader.Read"}, {"name": "http2headerFieldNameError.Error"}, {"name": "http2headerFieldValueError.Error"}, {"name": "http2netHTTPClientConn.Close"}, {"name": "http2netHTTPClientConn.RoundTrip"}, {"name": "http2noDialClientConnPool.GetClientConn"}, {"name": "http2noDialH2RoundTripper.NewClientConn"}, {"name": "http2noDialH2RoundTripper.RoundTrip"}, {"name": "http2pipe.Read"}, {"name": "http2priorityWriteSchedulerRFC7540.CloseStream"}, {"name": "http2priorityWriteSchedulerRFC7540.OpenStream"}, {"name": "http2priorityWriteSchedulerRFC7540.Pop"}, {"name": "http2priorityWriteSchedulerRFC9218.OpenStream"}, {"name": "http2priorityWriteSchedulerRFC9218.Pop"}, {"name": "http2pseudoHeaderError.Error"}, {"name": "http2randomWriteScheduler.Pop"}, {"name": "http2requestBody.Close"}, {"name": "http2requestBody.Read"}, {"name": "http2responseWriter.Flush"}, {"name": "http2responseWriter.FlushError"}, 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"1.27.2", "versionType": "semver"}], "packageName": "net/http/internal/http2", "collectionURL": "https://pkg.go.dev", "defaultStatus": "unaffected", "programRoutines": [{"name": "outflow.add"}, {"name": "outflow.available"}, {"name": "outflow.setConnFlow"}, {"name": "outflow.take"}, {"name": "Server.serveConn"}, {"name": "serverConn.newStream"}, {"name": "serverConn.processSettingInitialWindowSize"}, {"name": "serverConn.processWindowUpdate"}, {"name": "serverConn.scheduleFrameWrite"}, {"name": "ClientConn.addStreamLocked"}, {"name": "Transport.newClientConn"}, {"name": "clientConnReadLoop.processSettingsNoWrite"}, {"name": "clientConnReadLoop.processWindowUpdate"}, {"name": "clientConnReadLoop.streamByID"}, {"name": "clientStream.awaitFlowControl"}, {"name": "clientStream.cleanupWriteRequest"}, {"name": "FrameWriteRequest.Consume"}, {"name": "ClientConn.Close"}, {"name": "ClientConn.Ping"}, {"name": "ClientConn.RoundTrip"}, {"name": "ClientConn.Shutdown"}, {"name": "Framer.ReadFrame"}, {"name": "Framer.ReadFrameForHeader"}, {"name": "Framer.ReadFrameHeader"}, {"name": "Framer.WriteContinuation"}, {"name": "Framer.WriteData"}, {"name": "Framer.WriteDataPadded"}, {"name": "Framer.WriteGoAway"}, {"name": "Framer.WriteHeaders"}, {"name": "Framer.WritePing"}, {"name": "Framer.WritePriority"}, {"name": "Framer.WritePriorityUpdate"}, {"name": "Framer.WritePushPromise"}, {"name": "Framer.WriteRSTStream"}, {"name": "Framer.WriteRawFrame"}, {"name": "Framer.WriteSettings"}, {"name": "Framer.WriteSettingsAck"}, {"name": "Framer.WriteWindowUpdate"}, {"name": "NetHTTPClientConn.Close"}, {"name": "NetHTTPClientConn.Ping"}, {"name": "NetHTTPClientConn.RoundTrip"}, {"name": "ReadFrameHeader"}, {"name": "Server.GracefulShutdown"}, {"name": "Server.ServeConn"}, {"name": "SettingsFrame.ForeachSetting"}, {"name": "Transport.AddConn"}, {"name": "Transport.CloseIdleConnections"}, {"name": "Transport.NewClientConn"}, {"name": "Transport.RoundTrip"}, {"name": 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"ConfigureTransport"}, {"name": "ConfigureTransports"}, {"name": "ConnectionError.Error"}, {"name": "ErrCode.String"}, {"name": "FrameHeader.String"}, {"name": "FrameType.String"}, {"name": "FrameWriteRequest.String"}, {"name": "Framer.ReadFrame"}, {"name": "Framer.ReadFrameForHeader"}, {"name": "Framer.ReadFrameHeader"}, {"name": "Framer.WriteContinuation"}, {"name": "Framer.WriteData"}, {"name": "Framer.WriteDataPadded"}, {"name": "Framer.WriteGoAway"}, {"name": "Framer.WriteHeaders"}, {"name": "Framer.WritePing"}, {"name": "Framer.WritePriority"}, {"name": "Framer.WritePriorityUpdate"}, {"name": "Framer.WritePushPromise"}, {"name": "Framer.WriteRSTStream"}, {"name": "Framer.WriteRawFrame"}, {"name": "Framer.WriteSettings"}, {"name": "Framer.WriteSettingsAck"}, {"name": "Framer.WriteWindowUpdate"}, {"name": "GoAwayError.Error"}, {"name": "ReadFrameHeader"}, {"name": "Server.ServeConn"}, {"name": "Setting.String"}, {"name": "SettingID.String"}, {"name": 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{"name": "priorityWriteSchedulerRFC7540.Pop"}, {"name": "priorityWriteSchedulerRFC9218.OpenStream"}, {"name": "priorityWriteSchedulerRFC9218.Pop"}, {"name": "pseudoHeaderError.Error"}, {"name": "randomWriteScheduler.Pop"}, {"name": "requestBody.Close"}, {"name": "requestBody.Read"}, {"name": "responseWriter.Flush"}, {"name": "responseWriter.FlushError"}, {"name": "responseWriter.Push"}, {"name": "responseWriter.SetReadDeadline"}, {"name": "responseWriter.SetWriteDeadline"}, {"name": "responseWriter.Write"}, {"name": "responseWriter.WriteHeader"}, {"name": "responseWriter.WriteString"}, {"name": "roundRobinWriteScheduler.OpenStream"}, {"name": "roundRobinWriteScheduler.Pop"}, {"name": "serverConn.CloseConn"}, {"name": "serverConn.Flush"}, {"name": "stickyErrWriter.Write"}, {"name": "transportResponseBody.Close"}, {"name": "transportResponseBody.Read"}, {"name": "unencryptedTransport.RoundTrip"}, {"name": "writeData.String"}]}]}], "published": "2026-10-08T23:17:04.010", "references": [{"url": "https://go.dev/cl/847186", "source": "security@golang.org"}, {"url": "https://go.dev/cl/847308", "source": "security@golang.org"}, {"url": "https://go.dev/issue/81742", "source": "security@golang.org"}, {"url": "https://groups.google.com/g/golang-announce/c/U2fTuyDJznI", "source": "security@golang.org"}, {"url": "https://groups.google.com/g/golang-announce/c/ZPwCyRUuGBs", "source": "security@golang.org"}, {"url": "https://pkg.go.dev/vuln/GO-2026-6611", "source": "security@golang.org"}], "vulnStatus": "Awaiting Analysis", "weaknesses": [{"type": "Secondary", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "description": [{"lang": "en", "value": "CWE-405"}]}], "descriptions": [{"lang": "en", "value": "A malicious HTTP/2 peer can cause excessive CPU consumption in the client or server by opening a large number of streams and then sending many small SETTINGS frames containing SETTINGS_INITIAL_WINDOW_SIZE values."}], "lastModified": "2026-10-09T17:16:49.857", "sourceIdentifier": "security@golang.org"}