CVE-2026-78660

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-78660", "assignerOrgId": "1bb62c36-49e3-4200-9d77-64a1400537cc", "state": "PUBLISHED", "assignerShortName": "Go", "dateReserved": "2026-08-24T23:36:15.738Z", "datePublished": "2026-10-08T22:53:59.334Z", "dateUpdated": "2026-10-09T16:23:56.092Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "1bb62c36-49e3-4200-9d77-64a1400537cc", "shortName": "Go", "dateUpdated": "2026-10-08T22:53:59.334Z"}, "title": "HTTP/2 transport accepts malformed framing-related headers in net/http", "descriptions": [{"lang": "en", "value": "Historically, we have been rather lax about malformed framing-related headers in our HTTP/2 implementation, as they cannot interfere with HTTP/2 framing. However, this makes it possible for our HTTP/2 implementation to forward responses containing such headers to an HTTP/1 client when acting as a reverse proxy. If the HTTP/1 client also does not behave strictly enough, this can result in response smuggling."}], "affected": [{"vendor": "Go standard library", "product": "net/http", "collectionURL": "https://pkg.go.dev", "packageName": "net/http", "versions": [{"version": "0", "lessThan": "1.26.9", "status": "affected", "versionType": "semver"}], "programRoutines": [{"name": "http2clientConnReadLoop.handleResponse"}, {"name": "Client.CloseIdleConnections"}, {"name": "Client.Do"}, {"name": "Client.Get"}, {"name": "Client.Head"}, {"name": "Client.Post"}, {"name": "Client.PostForm"}, {"name": "ClientConn.Close"}, {"name": "ClientConn.RoundTrip"}, {"name": "Get"}, {"name": "Head"}, {"name": "Post"}, {"name": "PostForm"}, {"name": "Transport.CloseIdleConnections"}, {"name": "Transport.NewClientConn"}, {"name": "Transport.RoundTrip"}, {"name": "http1ClientConn.Close"}, {"name": "http1ClientConn.RoundTrip"}, {"name": "http2Transport.NewClientConn"}, {"name": "http2Transport.RoundTrip"}, {"name": "http2Transport.RoundTripOpt"}, {"name": "http2clientConnPool.GetClientConn"}, {"name": "http2noDialClientConnPool.GetClientConn"}, {"name": "http2noDialH2RoundTripper.NewClientConn"}, {"name": "http2noDialH2RoundTripper.RoundTrip"}, {"name": "http2unencryptedTransport.RoundTrip"}], "defaultStatus": "unaffected"}, {"vendor": "Go standard library", "product": "net/http/internal/http2", "collectionURL": "https://pkg.go.dev", "packageName": "net/http/internal/http2", "versions": [{"version": "1.27.0-0", "lessThan": "1.27.2", "status": "affected", "versionType": "semver"}], "programRoutines": [{"name": "clientConnReadLoop.handleResponse"}, {"name": "Transport.AddConn"}, {"name": "Transport.NewClientConn"}, {"name": "Transport.RoundTrip"}, {"name": "Transport.RoundTripOpt"}, {"name": "clientConnPool.GetClientConn"}, {"name": "noDialClientConnPool.GetClientConn"}], "defaultStatus": "unaffected"}, {"vendor": "golang.org/x/net", "product": "golang.org/x/net/http2", "collectionURL": "https://pkg.go.dev", "packageName": "golang.org/x/net/http2", "versions": [{"version": "0", "lessThan": "0.60.0", "status": "affected", "versionType": "semver"}], "programRoutines": [{"name": "clientConnReadLoop.handleResponse"}, {"name": "Transport.NewClientConn"}, {"name": "Transport.RoundTrip"}, {"name": "Transport.RoundTripOpt"}, {"name": "clientConnPool.GetClientConn"}, {"name": "noDialClientConnPool.GetClientConn"}, {"name": "noDialH2RoundTripper.NewClientConn"}, {"name": "noDialH2RoundTripper.RoundTrip"}, {"name": "unencryptedTransport.RoundTrip"}], "defaultStatus": "unaffected"}], "problemTypes": [{"descriptions": [{"lang": "en", "description": "CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')"}]}], "references": [{"url": "https://go.dev/cl/835145"}, {"url": "https://go.dev/cl/836385"}, {"url": "https://go.dev/issue/81115"}, {"url": "https://groups.google.com/g/golang-announce/c/U2fTuyDJznI"}, {"url": "https://pkg.go.dev/vuln/GO-2026-6610"}], "credits": [{"lang": "en", "value": "TJ Barton"}]}, "adp": [{"problemTypes": [{"descriptions": [{"type": "CWE", "cweId": "CWE-444", "lang": "en", "description": "CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')"}]}], "metrics": [{"cvssV3_1": {"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"}}, {"other": {"type": "ssvc", "content": {"timestamp": "2026-10-09T16:21:51.217328Z", "id": "CVE-2026-78660", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-09T16:23:56.092Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"cvssV3_1": {"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"}}, {"other": {"type": "ssvc", "content": {"id": "CVE-2026-78660", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2026-10-09T16:21:51.217328Z"}}}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-444", "description": "CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')"}]}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-09T16:19:44.882Z"}}], "cna": {"title": "HTTP/2 transport accepts malformed framing-related headers in net/http", "credits": [{"lang": "en", "value": "TJ Barton"}], "affected": [{"vendor": "Go standard library", "product": "net/http", "versions": [{"status": "affected", "version": "0", "lessThan": "1.26.9", "versionType": "semver"}], "packageName": "net/http", "collectionURL": "https://pkg.go.dev", "defaultStatus": "unaffected", "programRoutines": [{"name": "http2clientConnReadLoop.handleResponse"}, {"name": "Client.CloseIdleConnections"}, {"name": "Client.Do"}, {"name": "Client.Get"}, {"name": "Client.Head"}, {"name": "Client.Post"}, {"name": "Client.PostForm"}, {"name": "ClientConn.Close"}, {"name": "ClientConn.RoundTrip"}, {"name": "Get"}, {"name": "Head"}, {"name": "Post"}, {"name": "PostForm"}, {"name": "Transport.CloseIdleConnections"}, {"name": "Transport.NewClientConn"}, {"name": "Transport.RoundTrip"}, {"name": "http1ClientConn.Close"}, {"name": "http1ClientConn.RoundTrip"}, {"name": "http2Transport.NewClientConn"}, {"name": "http2Transport.RoundTrip"}, {"name": "http2Transport.RoundTripOpt"}, {"name": "http2clientConnPool.GetClientConn"}, {"name": "http2noDialClientConnPool.GetClientConn"}, {"name": "http2noDialH2RoundTripper.NewClientConn"}, {"name": "http2noDialH2RoundTripper.RoundTrip"}, {"name": "http2unencryptedTransport.RoundTrip"}]}, {"vendor": "Go standard library", "product": "net/http/internal/http2", "versions": [{"status": "affected", "version": "1.27.0-0", "lessThan": "1.27.2", "versionType": "semver"}], "packageName": "net/http/internal/http2", "collectionURL": "https://pkg.go.dev", "defaultStatus": "unaffected", "programRoutines": [{"name": "clientConnReadLoop.handleResponse"}, {"name": "Transport.AddConn"}, {"name": "Transport.NewClientConn"}, {"name": "Transport.RoundTrip"}, {"name": "Transport.RoundTripOpt"}, {"name": "clientConnPool.GetClientConn"}, {"name": "noDialClientConnPool.GetClientConn"}]}, {"vendor": "golang.org/x/net", "product": "golang.org/x/net/http2", "versions": [{"status": "affected", "version": "0", "lessThan": "0.60.0", "versionType": "semver"}], "packageName": "golang.org/x/net/http2", "collectionURL": "https://pkg.go.dev", "defaultStatus": "unaffected", "programRoutines": [{"name": "clientConnReadLoop.handleResponse"}, {"name": "Transport.NewClientConn"}, {"name": "Transport.RoundTrip"}, {"name": "Transport.RoundTripOpt"}, {"name": "clientConnPool.GetClientConn"}, {"name": "noDialClientConnPool.GetClientConn"}, {"name": "noDialH2RoundTripper.NewClientConn"}, {"name": "noDialH2RoundTripper.RoundTrip"}, {"name": "unencryptedTransport.RoundTrip"}]}], "references": [{"url": "https://go.dev/cl/835145"}, {"url": "https://go.dev/cl/836385"}, {"url": "https://go.dev/issue/81115"}, {"url": "https://groups.google.com/g/golang-announce/c/U2fTuyDJznI"}, {"url": "https://pkg.go.dev/vuln/GO-2026-6610"}], "descriptions": [{"lang": "en", "value": "Historically, we have been rather lax about malformed framing-related headers in our HTTP/2 implementation, as they cannot interfere with HTTP/2 framing. However, this makes it possible for our HTTP/2 implementation to forward responses containing such headers to an HTTP/1 client when acting as a reverse proxy. If the HTTP/1 client also does not behave strictly enough, this can result in response smuggling."}], "problemTypes": [{"descriptions": [{"lang": "en", "description": "CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')"}]}], "providerMetadata": {"orgId": "1bb62c36-49e3-4200-9d77-64a1400537cc", "shortName": "Go", "dateUpdated": "2026-10-08T22:53:59.334Z"}}}, "cveMetadata": {"cveId": "CVE-2026-78660", "state": "PUBLISHED", "dateUpdated": "2026-10-09T16:23:56.092Z", "dateReserved": "2026-08-24T23:36:15.738Z", "assignerOrgId": "1bb62c36-49e3-4200-9d77-64a1400537cc", "datePublished": "2026-10-08T22:53:59.334Z", "assignerShortName": "Go"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"collectionURL": "https://pkg.go.dev", "defaultStatus": "unaffected", "packageName": "net/http", "product": "net/http", "programRoutines": [{"name": "http2clientConnReadLoop.handleResponse"}, {"name": "Client.CloseIdleConnections"}, {"name": "Client.Do"}, {"name": "Client.Get"}, {"name": "Client.Head"}, {"name": "Client.Post"}, {"name": "Client.PostForm"}, {"name": "ClientConn.Close"}, {"name": "ClientConn.RoundTrip"}, {"name": "Get"}, {"name": "Head"}, {"name": "Post"}, {"name": "PostForm"}, {"name": "Transport.CloseIdleConnections"}, {"name": "Transport.NewClientConn"}, {"name": "Transport.RoundTrip"}, {"name": "http1ClientConn.Close"}, {"name": "http1ClientConn.RoundTrip"}, {"name": "http2Transport.NewClientConn"}, {"name": "http2Transport.RoundTrip"}, {"name": "http2Transport.RoundTripOpt"}, {"name": "http2clientConnPool.GetClientConn"}, {"name": "http2noDialClientConnPool.GetClientConn"}, {"name": "http2noDialH2RoundTripper.NewClientConn"}, {"name": "http2noDialH2RoundTripper.RoundTrip"}, {"name": "http2unencryptedTransport.RoundTrip"}], "vendor": "Go standard library", "versions": [{"lessThan": "1.26.9", "status": "affected", "version": "0", "versionType": "semver"}]}, {"collectionURL": "https://pkg.go.dev", "defaultStatus": "unaffected", "packageName": "net/http/internal/http2", "product": "net/http/internal/http2", "programRoutines": [{"name": "clientConnReadLoop.handleResponse"}, {"name": "Transport.AddConn"}, {"name": "Transport.NewClientConn"}, {"name": "Transport.RoundTrip"}, {"name": "Transport.RoundTripOpt"}, {"name": "clientConnPool.GetClientConn"}, {"name": "noDialClientConnPool.GetClientConn"}], "vendor": "Go standard library", "versions": [{"lessThan": "1.27.2", "status": "affected", "version": "1.27.0-0", "versionType": "semver"}]}, {"collectionURL": "https://pkg.go.dev", "defaultStatus": "unaffected", "packageName": "golang.org/x/net/http2", "product": "golang.org/x/net/http2", "programRoutines": [{"name": "clientConnReadLoop.handleResponse"}, {"name": "Transport.NewClientConn"}, {"name": "Transport.RoundTrip"}, {"name": "Transport.RoundTripOpt"}, {"name": "clientConnPool.GetClientConn"}, {"name": "noDialClientConnPool.GetClientConn"}, {"name": "noDialH2RoundTripper.NewClientConn"}, {"name": "noDialH2RoundTripper.RoundTrip"}, {"name": "unencryptedTransport.RoundTrip"}], "vendor": "golang.org/x/net", "versions": [{"lessThan": "0.60.0", "status": "affected", "version": "0", "versionType": "semver"}]}], "source": "security@golang.org"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Historically, we have been rather lax about malformed framing-related headers in our HTTP/2 implementation, as they cannot interfere with HTTP/2 framing. However, this makes it possible for our HTTP/2 implementation to forward responses containing such headers to an HTTP/1 client when acting as a reverse proxy. If the HTTP/1 client also does not behave strictly enough, this can result in response smuggling."}], "id": "CVE-2026-78660", "lastModified": "2026-10-09T17:16:49.243", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-78660", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-10-09T16:21:51.217328Z", "version": "2.0.3"}}]}, "published": "2026-10-08T23:17:03.510", "references": [{"source": "security@golang.org", "url": "https://go.dev/cl/835145"}, {"source": "security@golang.org", "url": "https://go.dev/cl/836385"}, {"source": "security@golang.org", "url": "https://go.dev/issue/81115"}, {"source": "security@golang.org", "url": "https://groups.google.com/g/golang-announce/c/U2fTuyDJznI"}, {"source": "security@golang.org", "url": "https://pkg.go.dev/vuln/GO-2026-6610"}], "sourceIdentifier": "security@golang.org", "vulnStatus": "Awaiting Analysis", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-444"}], "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[0,1.26.9)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "net/http", "source": "cna", "vendor": "Go standard library"}, "product": "net/http", "vendor": "go_standard_library"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[1.27.0-0,1.27.2)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "manual", "scores": [{"score": 100.0, "source": "manual"}]}, "original": {"product": "net/http/internal/http2", "source": "cna", "vendor": "Go standard library"}, "product": "net/http", "vendor": "go_standard_library"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[0,0.60.0)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "manual", "scores": [{"score": 100.0, "source": "manual"}]}, "original": {"product": "golang.org/x/net/http2", "source": "cna", "vendor": "golang.org/x/net"}, "product": "net/http2", "vendor": "go_standard_library"}], "created": "2026-10-09T02:00:23.644626+00:00", "updated": "2026-10-09T20:30:11.830569+00:00", "vendors": ["go_standard_library", "go_standard_library$PRODUCT$net/http", "go_standard_library$PRODUCT$net/http2"]}