{"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": "2026-10-08T22:53:59.334Z"}, "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"}]}}}

{}

{"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": "2026-10-08T23:17:03.510", "metrics": {}, "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": "Received"}

{}

{"created": "2026-10-09T02:00:23.644626+00:00", "updated": "2026-10-09T02:00:23.644640+00:00", "vendors": [], "weaknesses": ["CWE-20"]}