{"record":{"id":"76e02517c19764f4","repo":"gravitational/teleport","slug":"proto-createauthenticatechallengerequest-illegal","errorCode":null,"errorMessage":"proto: CreateAuthenticateChallengeRequest: illegal tag %d (wire type %d)","messagePattern":"proto: CreateAuthenticateChallengeRequest: illegal tag (.+?) \\(wire type (.+?)\\)","errorType":"validation","errorClass":null,"httpStatus":null,"severity":"error","filePath":"api/client/proto/authservice.pb.go","lineNumber":60033,"sourceCode":"\t\t\t\treturn ErrIntOverflowAuthservice\n\t\t\t}\n\t\t\tif iNdEx >= l {\n\t\t\t\treturn io.ErrUnexpectedEOF\n\t\t\t}\n\t\t\tb := dAtA[iNdEx]\n\t\t\tiNdEx++\n\t\t\twire |= uint64(b&0x7F) << shift\n\t\t\tif b < 0x80 {\n\t\t\t\tbreak\n\t\t\t}\n\t\t}\n\t\tfieldNum := int32(wire >> 3)\n\t\twireType := int(wire & 0x7)\n\t\tif wireType == 4 {\n\t\t\treturn fmt.Errorf(\"proto: CreateAuthenticateChallengeRequest: wiretype end group for non-group\")\n\t\t}\n\t\tif fieldNum <= 0 {\n\t\t\treturn fmt.Errorf(\"proto: CreateAuthenticateChallengeRequest: illegal tag %d (wire type %d)\", fieldNum, wire)\n\t\t}\n\t\tswitch fieldNum {\n\t\tcase 1:\n\t\t\tif wireType != 2 {\n\t\t\t\treturn fmt.Errorf(\"proto: wrong wireType = %d for field UserCredentials\", wireType)\n\t\t\t}\n\t\t\tvar msglen int\n\t\t\tfor shift := uint(0); ; shift += 7 {\n\t\t\t\tif shift >= 64 {\n\t\t\t\t\treturn ErrIntOverflowAuthservice\n\t\t\t\t}\n\t\t\t\tif iNdEx >= l {\n\t\t\t\t\treturn io.ErrUnexpectedEOF\n\t\t\t\t}\n\t\t\t\tb := dAtA[iNdEx]\n\t\t\t\tiNdEx++\n\t\t\t\tmsglen |= int(b&0x7F) << shift\n\t\t\t\tif b < 0x80 {","sourceCodeStart":60015,"sourceCodeEnd":60051,"githubUrl":"https://github.com/gravitational/teleport/blob/1283425b60ec5f60d509ba4c791183d452923ff7/api/client/proto/authservice.pb.go#L60015-L60051","documentation":"Generated Unmarshal code for CreateAuthenticateChallengeRequest returned an illegal-tag error: fieldNum<=0 or an unknown/unskippable field. The stream deviates from the expected schema for this message.","triggerScenarios":"Decoding payload with an invalid or unrecognized field tag in CreateAuthenticateChallengeRequest, typically from mismatched proto versions or corrupted bytes.","commonSituations":"Client compiled against older proto where field numbers differ; proxy/intermediary rewriting messages; payload corruption in transit.","solutions":["Rebuild client and server against the same proto file versions","Verify no middleware mutates or repackages the gRPC frame","Validate payload structure with protoc --decode_raw","Pin the api module version on both sides of the connection"],"exampleFix":null,"handlingStrategy":"try-catch","validationCode":"if len(payload) < 2 { return errors.New(\"payload too short for a protobuf message\") }","typeGuard":null,"tryCatchPattern":"var req proto.CreateAuthenticateChallengeRequest\nif err := proto.Unmarshal(payload, &req); err != nil {\n  return trace.AccessDenied(\"malformed challenge request\")\n}","preventionTips":["Never remove or reuse proto field numbers without a major version bump","Verify intermediaries don't rewrite gRPC frames","Test cross-version compatibility in CI","Regenerate .pb.go after every proto change and commit together"],"tags":["protobuf","grpc","deserialization","version-skew"],"backgroundTag":"protobuf-unmarshal-failed","analyzedSha":"1283425b60ec5f60d509ba4c791183d452923ff7","analyzedAt":"2026-09-02T04:06:41.601Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-08T10:18:20.063Z"}