diff --git a/auth/auth.go b/auth/auth.go
index c9c77a1c6..8775ad6e9 100644
--- a/auth/auth.go
+++ b/auth/auth.go
@@ -81,13 +81,12 @@ func New(ctx context.Context, log *zap.Logger, s store.Storer, opt options.AuthO
 		handlers.GetLinks().OAuth2AuthorizeClient,
 	))
 
-	oauth2Server.SetClientAuthorizedHandler(func(id string, grant oauth2def.GrantType) (bool, error) {
+	oauth2Server.SetClientAuthorizedHandler(func(id string, grant oauth2def.GrantType) (allowed bool, err error) {
 		// this is a bit silly and a bad design of the oauth2 server lib
 		// why do we need to keep on load the client??
 		var (
 			clientID uint64
 			client   *types.AuthClient
-			err      error
 		)
 
 		clientID, err = strconv.ParseUint(id, 10, 64)
@@ -108,7 +107,7 @@ func New(ctx context.Context, log *zap.Logger, s store.Storer, opt options.AuthO
 		return true, nil
 	})
 
-	oauth2Server.SetClientScopeHandler(func(id, ss string) (allowed bool, err error) {
+	oauth2Server.SetClientScopeHandler(func(tgr *oauth2def.TokenGenerateRequest) (allowed bool, err error) {
 		// this is a bit silly and a bad design of the oauth2 server lib
 		// why do we need to keep on load the client??
 		var (
@@ -116,7 +115,7 @@ func New(ctx context.Context, log *zap.Logger, s store.Storer, opt options.AuthO
 			client   *types.AuthClient
 		)
 
-		clientID, err = strconv.ParseUint(id, 10, 64)
+		clientID, err = strconv.ParseUint(tgr.ClientID, 10, 64)
 		if err != nil {
 			return false, fmt.Errorf("could not authorize client: %w", err)
 		}
@@ -127,7 +126,7 @@ func New(ctx context.Context, log *zap.Logger, s store.Storer, opt options.AuthO
 		}
 
 		// ensure all requested scopes are allowed on a client
-		for _, scope := range strings.Split(ss, " ") {
+		for _, scope := range strings.Split(tgr.Scope, " ") {
 			if !auth.CheckScope(client.Scope, scope) {
 				return false, fmt.Errorf("client does not allow use of '%s' scope", scope)
 			}
diff --git a/auth/handlers/handle_oauth2.go b/auth/handlers/handle_oauth2.go
index d005dcb63..292970149 100644
--- a/auth/handlers/handle_oauth2.go
+++ b/auth/handlers/handle_oauth2.go
@@ -160,22 +160,10 @@ func (h AuthHandlers) oauth2Token(req *request.AuthReq) (err error) {
 	client, err := h.loadRequestedClient(req)
 
 	if err != nil {
-		return
+		return h.tokenError(req.Response, err)
 	}
 
-	if err = client.Verify(); err != nil {
-		return fmt.Errorf("invalid client: %w", err)
-	} else {
-		// add client to context so we can reach it from client store via context.Value() fn
-		//
-		// this way we work around the limitations we have with the oauth2 lib.
-		r := req.Request.Clone(context.WithValue(req.Context(), &oauth2.ContextClientStore{}, client))
-
-		// handle token request with extended context that now holds client!
-		err = h.OAuth2.HandleTokenRequest(req.Response, r)
-	}
-
-	return
+	return h.handleTokenRequest(req, client)
 }
 
 func (h AuthHandlers) oauth2Info(w http.ResponseWriter, r *http.Request) {
@@ -289,8 +277,9 @@ func (h AuthHandlers) oauth2authorizeDefaultClientProc(req *request.AuthReq) (er
 		h.DefaultClient.Secret,
 	)
 
-	req.Status = -1
-	return h.OAuth2.HandleTokenRequest(req.Response, r)
+	req.Request = r
+
+	return h.handleTokenRequest(req, h.DefaultClient)
 }
 
 func (h AuthHandlers) verifyDefaultClient() error {
@@ -356,6 +345,58 @@ func (h AuthHandlers) loadRequestedClient(req *request.AuthReq) (client *types.A
 	}()
 }
 
+func (h AuthHandlers) handleTokenRequest(req *request.AuthReq, client *types.AuthClient) error {
+	req.Status = -1
+
+	var (
+		r   = req.Request
+		w   = req.Response
+		ctx = req.Context()
+	)
+
+	req.Status = -1
+
+	if err := client.Verify(); err != nil {
+		return h.tokenError(w, fmt.Errorf("invalid client: %w", err))
+	}
+
+	// add client to context so we can reach it from client store via context.Value() fn
+	// this way we work around the limitations we have with the oauth2 lib.
+	ctx = context.WithValue(ctx, &oauth2.ContextClientStore{}, client)
+	r = req.Request.Clone(ctx)
+
+	gt, tgr, err := h.OAuth2.ValidationTokenRequest(r)
+	if err != nil {
+		return h.tokenError(w, err)
+	}
+
+	if gt == oauth2def.ClientCredentials {
+		// Authenticated with client credentials!
+		//
+		// We'll use info from client security
+		if client.Security == nil || client.Security.ImpersonateUser == 0 {
+			return h.tokenError(w, errors.Internal("auth client security configuration invalid"))
+		}
+
+		tgr.UserID = strings.Join(append(
+			[]string{fmt.Sprintf("%d", client.Security.ImpersonateUser)},
+			client.Security.ForcedRoles...,
+		), " ")
+	}
+
+	ti, err := h.OAuth2.GetAccessToken(ctx, gt, tgr)
+	if err != nil {
+		return h.tokenError(w, err)
+	}
+
+	return token(w, h.OAuth2.GetTokenData(ti), nil)
+}
+
+func (h AuthHandlers) tokenError(w http.ResponseWriter, err error) error {
+	data, statusCode, header := h.OAuth2.GetErrorData(err)
+	return token(w, data, header, statusCode)
+}
+
 func SubSplit(ti oauth2def.TokenInfo, data map[string]interface{}) {
 	userIdWithRoles := strings.SplitN(ti.GetUserID(), " ", 2)
 	data["sub"] = userIdWithRoles[0]
@@ -395,3 +436,21 @@ func Profile(ctx context.Context, ti oauth2def.TokenInfo, data map[string]interf
 
 	return nil
 }
+
+func token(w http.ResponseWriter, data map[string]interface{}, header http.Header, statusCode ...int) error {
+	w.Header().Set("Content-Type", "application/json;charset=UTF-8")
+	w.Header().Set("Cache-Control", "no-store")
+	w.Header().Set("Pragma", "no-cache")
+
+	for key := range header {
+		w.Header().Set(key, header.Get(key))
+	}
+
+	status := http.StatusOK
+	if len(statusCode) > 0 && statusCode[0] > 0 {
+		status = statusCode[0]
+	}
+
+	w.WriteHeader(status)
+	return json.NewEncoder(w).Encode(data)
+}
diff --git a/auth/oauth2/corteza_token_store.go b/auth/oauth2/corteza_token_store.go
index 3e09df262..13065e2aa 100644
--- a/auth/oauth2/corteza_token_store.go
+++ b/auth/oauth2/corteza_token_store.go
@@ -83,7 +83,7 @@ func (c CortezaTokenStore) Create(ctx context.Context, info oauth2.TokenInfo) (e
 	if info.GetUserID() != "" {
 		if oa2t.UserID = auth.ExtractUserIDFromSubClaim(info.GetUserID()); oa2t.UserID == 0 {
 			// UserID stores collection of IDs: user's ID and set of all roles user is member of
-			return fmt.Errorf("could not parse user ID from token info: %w", err)
+			return fmt.Errorf("could not parse user ID from token info")
 		}
 	}
 
diff --git a/auth/oauth2/oauth2.go b/auth/oauth2/oauth2.go
index 8b9ce0f2e..8f1c478b1 100644
--- a/auth/oauth2/oauth2.go
+++ b/auth/oauth2/oauth2.go
@@ -71,8 +71,7 @@ func NewServer(manager *manage.Manager) *server.Server {
 			oauth2.Refreshing,
 			// before enabling ClientCredentials grant type, we need to know how to modify released token
 			// using client's security info; how to enforce impersonated user and his roles.
-			//
-			// oauth2.ClientCredentials,
+			oauth2.ClientCredentials,
 		},
 		AllowedCodeChallengeMethods: []oauth2.CodeChallengeMethod{
 			oauth2.CodeChallengePlain,
diff --git a/auth/oauth2/user_authorizer.go b/auth/oauth2/user_authorizer.go
index 4d4331f6b..3cf5ba6be 100644
--- a/auth/oauth2/user_authorizer.go
+++ b/auth/oauth2/user_authorizer.go
@@ -9,6 +9,7 @@ import (
 
 func NewUserAuthorizer(sm *request.SessionManager, loginURL, clientAuthURL string) server.UserAuthorizationHandler {
 	return func(w http.ResponseWriter, r *http.Request) (identity string, err error) {
+
 		var (
 			ses    = sm.Get(r)
 			au     = request.GetAuthUser(ses)
diff --git a/go.mod b/go.mod
index 4433ab157..768f089c7 100644
--- a/go.mod
+++ b/go.mod
@@ -28,7 +28,7 @@ require (
 	github.com/go-chi/cors v1.0.0
 	github.com/go-chi/httprate v0.4.0
 	github.com/go-chi/jwtauth v0.0.0-20190109153619-47840abb19b3
-	github.com/go-oauth2/oauth2/v4 v4.2.0
+	github.com/go-oauth2/oauth2/v4 v4.3.0
 	github.com/go-sql-driver/mysql v1.5.0
 	github.com/golang/mock v1.4.4
 	github.com/golang/protobuf v1.4.2
@@ -55,7 +55,6 @@ require (
 	github.com/pkg/errors v0.9.1
 	github.com/pquerna/cachecontrol v0.0.0-20180517163645-1555304b9b35 // indirect
 	github.com/prometheus/client_golang v0.9.3
-	github.com/quasoft/memstore v0.0.0-20191010062613-2bce066d2b0b // indirect
 	github.com/rwcarlsen/goexif v0.0.0-20190401172101-9e8deecbddbd // indirect
 	github.com/sony/sonyflake v0.0.0-20181109022403-6d5bd6181009
 	github.com/spf13/afero v1.2.2
diff --git a/go.sum b/go.sum
index 5e05f5152..c2cfc566b 100644
--- a/go.sum
+++ b/go.sum
@@ -51,8 +51,6 @@ github.com/Masterminds/squirrel v1.1.1-0.20191017225151-12f2162c8d8d/go.mod h1:y
 github.com/OneOfOne/xxhash v1.2.2/go.mod h1:HSdplMjZKSmBqAxg5vPj2TmRDmfkzw+cTzAElWljhcU=
 github.com/PaesslerAG/gval v0.1.1/go.mod h1:y/nm5yEyTeX6av0OfKJNp9rBNj2XrGhAf5+v24IBN1I=
 github.com/PaesslerAG/gval v1.0.0/go.mod h1:y/nm5yEyTeX6av0OfKJNp9rBNj2XrGhAf5+v24IBN1I=
-github.com/PaesslerAG/gval v1.1.0 h1:k3RuxeZDO3eejD4cMPSt+74tUSvTnbGvLx0df4mdwFc=
-github.com/PaesslerAG/gval v1.1.0/go.mod h1:y/nm5yEyTeX6av0OfKJNp9rBNj2XrGhAf5+v24IBN1I=
 github.com/PaesslerAG/gval v1.1.1-0.20201104175134-7847ed0c7671 h1:mXmNWMJr5OPcaA00ryiN+FZphVa1EtUYiVNH8nfWALY=
 github.com/PaesslerAG/gval v1.1.1-0.20201104175134-7847ed0c7671/go.mod h1:Fa8gfkCmUsELXgayr8sfL/sw+VzCVoa03dcOcR/if2w=
 github.com/PaesslerAG/jsonpath v0.1.0/go.mod h1:4BzmtoM/PI8fPO4aQGIusjGxGir2BzcV0grWtFzq1Y8=
@@ -136,6 +134,8 @@ github.com/go-logfmt/logfmt v0.3.0/go.mod h1:Qt1PoO58o5twSAckw1HlFXLmHsOX5/0LbT9
 github.com/go-logfmt/logfmt v0.4.0/go.mod h1:3RMwSq7FuexP4Kalkev3ejPJsZTpXXBr9+V4qmtdjCk=
 github.com/go-oauth2/oauth2/v4 v4.2.0 h1:wz9w9SwHrzC58XniFSGXIfl2R5Q6x1aecVuL/QBupl8=
 github.com/go-oauth2/oauth2/v4 v4.2.0/go.mod h1:+rsyi0o/ZbSfhL/3Xr/sAtL4brS+IdGj86PHVlPjE+4=
+github.com/go-oauth2/oauth2/v4 v4.3.0 h1:vp4goUmrq1YaPzpm34FDLlZiAkIqK3LsuNTTRyTnPbo=
+github.com/go-oauth2/oauth2/v4 v4.3.0/go.mod h1:+rsyi0o/ZbSfhL/3Xr/sAtL4brS+IdGj86PHVlPjE+4=
 github.com/go-session/session v3.1.2+incompatible/go.mod h1:8B3iivBQjrz/JtC68Np2T1yBBLxTan3mn/3OM0CyRt0=
 github.com/go-sql-driver/mysql v1.4.0/go.mod h1:zAC/RDZ24gD3HViQzih4MyKcchzm+sOG5ZlKdlhCg5w=
 github.com/go-sql-driver/mysql v1.5.0 h1:ozyZYNQW3x3HtqT1jira07DN2PArx2v7/mN66gGcHOs=
@@ -320,8 +320,6 @@ github.com/prometheus/procfs v0.0.0-20181005140218-185b4288413d/go.mod h1:c3At6R
 github.com/prometheus/procfs v0.0.0-20190507164030-5867b95ac084 h1:sofwID9zm4tzrgykg80hfFph1mryUeLRsUfoocVVmRY=
 github.com/prometheus/procfs v0.0.0-20190507164030-5867b95ac084/go.mod h1:TjEm7ze935MbeOT/UhFTIMYKhuLP4wbCsTZCD3I8kEA=
 github.com/prometheus/tsdb v0.7.1/go.mod h1:qhTCs0VvXwvX/y3TZrWD7rabWM+ijKTux40TwIPHuXU=
-github.com/quasoft/memstore v0.0.0-20191010062613-2bce066d2b0b h1:aUNXCGgukb4gtY99imuIeoh8Vr0GSwAlYxPAhqZrpFc=
-github.com/quasoft/memstore v0.0.0-20191010062613-2bce066d2b0b/go.mod h1:wTPjTepVu7uJBYgZ0SdWHQlIas582j6cn2jgk4DDdlg=
 github.com/rogpeppe/go-internal v1.3.0/go.mod h1:M8bDsm7K2OlrFYOpmOWEs/qY81heoFRclV5y23lUDJ4=
 github.com/rwcarlsen/goexif v0.0.0-20190401172101-9e8deecbddbd h1:CmH9+J6ZSsIjUK3dcGsnCnO41eRBOnY12zwkn5qVwgc=
 github.com/rwcarlsen/goexif v0.0.0-20190401172101-9e8deecbddbd/go.mod h1:hPqNNc0+uJM6H+SuU8sEs5K5IQeKccPqeSjfgcKGgPk=
@@ -411,8 +409,6 @@ go.uber.org/multierr v1.5.0 h1:KCa4XfM8CWFCpxXRGok+Q0SS/0XBhMDbHHGABQLvD2A=
 go.uber.org/multierr v1.5.0/go.mod h1:FeouvMocqHpRaaGuG9EjoKcStLC43Zu/fmqdUMPcKYU=
 go.uber.org/tools v0.0.0-20190618225709-2cfd321de3ee h1:0mgffUl7nfd+FpvXMVz4IDEaUSmT1ysygQC7qYo7sG4=
 go.uber.org/tools v0.0.0-20190618225709-2cfd321de3ee/go.mod h1:vJERXedbb3MVM5f9Ejo0C68/HhF8uaILCdgjnY+goOA=
-go.uber.org/zap v1.15.0 h1:ZZCA22JRF2gQE5FoNmhmrf7jeJJ2uhqDUNRYKm8dvmM=
-go.uber.org/zap v1.15.0/go.mod h1:Mb2vm2krFEG5DV0W9qcHBYFtp/Wku1cvYaqPsS/WYfc=
 go.uber.org/zap v1.16.0 h1:uFRZXykJGK9lLY4HtgSw44DnIcAM+kRBP7x5m+NpAOM=
 go.uber.org/zap v1.16.0/go.mod h1:MA8QOfq0BHJwdXa996Y4dYkAqRKB8/1K1QMMZVaNZjQ=
 golang.org/x/crypto v0.0.0-20180904163835-0709b304e793/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
diff --git a/pkg/auth/middleware.go b/pkg/auth/middleware.go
index 1ecf8e589..5a025f1e3 100644
--- a/pkg/auth/middleware.go
+++ b/pkg/auth/middleware.go
@@ -7,19 +7,29 @@ import (
 )
 
 func MiddlewareValidOnly(next http.Handler) http.Handler {
-	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		var ctx = r.Context()
+	return AccessTokenCheck("api")(next)
+}
 
-		if !CheckScope(ctx.Value(scopeCtxKey{}), "api") {
-			api.Send(w, r, errors.New("Unauthorized scope"))
-			return
-		}
+func AccessTokenCheck(scope ...string) func(http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			var ctx = r.Context()
 
-		if !GetIdentityFromContext(ctx).Valid() {
-			api.Send(w, r, errors.New("Unauthorized"))
-			return
-		}
+			for _, s := range scope {
+				if !CheckScope(ctx.Value(scopeCtxKey{}), s) {
+					w.WriteHeader(http.StatusUnauthorized)
+					api.Send(w, r, errors.New("unauthorized scope"))
+					return
+				}
+			}
 
-		next.ServeHTTP(w, r)
-	})
+			if !GetIdentityFromContext(ctx).Valid() {
+				w.WriteHeader(http.StatusUnauthorized)
+				api.Send(w, r, errors.New("unauthorized"))
+				return
+			}
+
+			next.ServeHTTP(w, r)
+		})
+	}
 }
diff --git a/system/types/auth_client.go b/system/types/auth_client.go
index 5179a4085..d058bb2ec 100644
--- a/system/types/auth_client.go
+++ b/system/types/auth_client.go
@@ -12,7 +12,6 @@ import (
 )
 
 type (
-	// AuthClient - An organisation may have many authClients. AuthClients may have many channels available. Access to channels may be shared between authClients.
 	AuthClient struct {
 		ID uint64 `json:"authClientID,string"`
 
@@ -70,7 +69,7 @@ type (
 	AuthClientSecurity struct {
 		// Impersonates a specific user;
 		// ignored when non client-credentials grant is used
-		//ImpersonateUser uint64 `json:"impersonateUser,string,omitempty"`
+		ImpersonateUser uint64 `json:"impersonateUser,string,omitempty"`
 
 		// Subset of roles, permitted to be used with this client
 		// IDs are intentionally stored as strings to support JS (int64 only)
@@ -146,7 +145,7 @@ func (set AuthClientSet) FindByHandle(handle string) *AuthClient {
 
 func (r *AuthClient) Verify() error {
 	switch {
-	case !r.Enabled:
+	case r == nil || !r.Enabled:
 		return fmt.Errorf("disabled")
 	case r.ExpiresAt != nil && r.ExpiresAt.After(time.Now()):
 		return fmt.Errorf("expired")
diff --git a/system/types/role.go b/system/types/role.go
index 09d3a6a0e..46d6088b2 100644
--- a/system/types/role.go
+++ b/system/types/role.go
@@ -8,7 +8,6 @@ import (
 )
 
 type (
-	// Role - An organisation may have many roles. Roles may have many channels available. Access to channels may be shared between roles.
 	Role struct {
 		ID     uint64 `json:"roleID,string"`
 		Name   string `json:"name"`
diff --git a/vendor/github.com/go-oauth2/oauth2/v4/README.md b/vendor/github.com/go-oauth2/oauth2/v4/README.md
index cb05e2834..d55587550 100644
--- a/vendor/github.com/go-oauth2/oauth2/v4/README.md
+++ b/vendor/github.com/go-oauth2/oauth2/v4/README.md
@@ -2,11 +2,11 @@
 
 > An open protocol to allow secure authorization in a simple and standard method from web, mobile and desktop applications.
 
-[![Build][Build-Status-Image]][Build-Status-Url] [![Codecov][codecov-image]][codecov-url] [![ReportCard][reportcard-image]][reportcard-url] [![GoDoc][godoc-image]][godoc-url] [![License][license-image]][license-url]
+[![Build][build-status-image]][build-status-url] [![Codecov][codecov-image]][codecov-url] [![ReportCard][reportcard-image]][reportcard-url] [![GoDoc][godoc-image]][godoc-url] [![License][license-image]][license-url]
 
 ## Protocol Flow
 
-``` text
+```text
      +--------+                               +---------------+
      |        |--(A)- Authorization Request ->|   Resource    |
      |        |                               |     Owner     |
@@ -30,13 +30,13 @@
 
 ### Download and install
 
-``` bash
+```bash
 go get -u -v github.com/go-oauth2/oauth2/v4/...
 ```
 
 ### Create file `server.go`
 
-``` go
+```go
 package main
 
 import (
@@ -95,7 +95,7 @@ func main() {
 
 ### Build and run
 
-``` bash
+```bash
 go build server.go
 
 ./server
@@ -105,24 +105,24 @@ go build server.go
 
 [http://localhost:9096/token?grant_type=client_credentials&client_id=000000&client_secret=999999&scope=read](http://localhost:9096/token?grant_type=client_credentials&client_id=000000&client_secret=999999&scope=read)
 
-``` json
+```json
 {
-    "access_token": "J86XVRYSNFCFI233KXDL0Q",
-    "expires_in": 7200,
-    "scope": "read",
-    "token_type": "Bearer"
+  "access_token": "J86XVRYSNFCFI233KXDL0Q",
+  "expires_in": 7200,
+  "scope": "read",
+  "token_type": "Bearer"
 }
 ```
 
 ## Features
 
-* Easy to use
-* Based on the [RFC 6749](https://tools.ietf.org/html/rfc6749) implementation
-* Token storage support TTL
-* Support custom expiration time of the access token
-* Support custom extension field
-* Support custom scope
-* Support jwt to generate access tokens
+- Easy to use
+- Based on the [RFC 6749](https://tools.ietf.org/html/rfc6749) implementation
+- Token storage support TTL
+- Support custom expiration time of the access token
+- Support custom extension field
+- Support custom scope
+- Support jwt to generate access tokens
 
 ## Example
 
@@ -161,27 +161,28 @@ if !ok || !token.Valid {
 
 ## Store Implements
 
-* [BuntDB](https://github.com/tidwall/buntdb)(default store)
-* [Redis](https://github.com/go-oauth2/redis)
-* [MongoDB](https://github.com/go-oauth2/mongo)
-* [MySQL](https://github.com/go-oauth2/mysql)
-* [MySQL (Provides both client and token store)](https://github.com/imrenagi/go-oauth2-mysql) 
-* [PostgreSQL](https://github.com/vgarvardt/go-oauth2-pg)
-* [DynamoDB](https://github.com/contamobi/go-oauth2-dynamodb)
-* [XORM](https://github.com/techknowlogick/go-oauth2-xorm)
-* [GORM](https://github.com/techknowlogick/go-oauth2-gorm)
-* [Firestore](https://github.com/tslamic/go-oauth2-firestore)
+- [BuntDB](https://github.com/tidwall/buntdb)(default store)
+- [Redis](https://github.com/go-oauth2/redis)
+- [MongoDB](https://github.com/go-oauth2/mongo)
+- [MySQL](https://github.com/go-oauth2/mysql)
+- [MySQL (Provides both client and token store)](https://github.com/imrenagi/go-oauth2-mysql)
+- [PostgreSQL](https://github.com/vgarvardt/go-oauth2-pg)
+- [DynamoDB](https://github.com/contamobi/go-oauth2-dynamodb)
+- [XORM](https://github.com/techknowlogick/go-oauth2-xorm)
+- [XORM (MySQL, client and token store)](https://github.com/rainlay/go-oauth2-xorm)
+- [GORM](https://github.com/techknowlogick/go-oauth2-gorm)
+- [Firestore](https://github.com/tslamic/go-oauth2-firestore)
 
 ## Handy Utilities
 
-* [OAuth2 Proxy Logger (Debug utility that proxies interfaces and logs)](https://github.com/aubelsb2/oauth2-logger-proxy)
+- [OAuth2 Proxy Logger (Debug utility that proxies interfaces and logs)](https://github.com/aubelsb2/oauth2-logger-proxy)
 
 ## MIT License
 
-  Copyright (c) 2016 Lyric
+Copyright (c) 2016 Lyric
 
-[Build-Status-Url]: https://travis-ci.org/go-oauth2/oauth2
-[Build-Status-Image]: https://travis-ci.org/go-oauth2/oauth2.svg?branch=master
+[build-status-url]: https://travis-ci.org/go-oauth2/oauth2
+[build-status-image]: https://travis-ci.org/go-oauth2/oauth2.svg?branch=master
 [codecov-url]: https://codecov.io/gh/go-oauth2/oauth2
 [codecov-image]: https://codecov.io/gh/go-oauth2/oauth2/branch/master/graph/badge.svg
 [reportcard-url]: https://goreportcard.com/report/github.com/go-oauth2/oauth2/v4
diff --git a/vendor/github.com/go-oauth2/oauth2/v4/server/handler.go b/vendor/github.com/go-oauth2/oauth2/v4/server/handler.go
index a5fd13904..bb2c6d811 100644
--- a/vendor/github.com/go-oauth2/oauth2/v4/server/handler.go
+++ b/vendor/github.com/go-oauth2/oauth2/v4/server/handler.go
@@ -16,7 +16,7 @@ type (
 	ClientAuthorizedHandler func(clientID string, grant oauth2.GrantType) (allowed bool, err error)
 
 	// ClientScopeHandler check the client allows to use scope
-	ClientScopeHandler func(clientID, scope string) (allowed bool, err error)
+	ClientScopeHandler func(tgr *oauth2.TokenGenerateRequest) (allowed bool, err error)
 
 	// UserAuthorizationHandler get user id from request authorization
 	UserAuthorizationHandler func(w http.ResponseWriter, r *http.Request) (userID string, err error)
@@ -25,9 +25,9 @@ type (
 	PasswordAuthorizationHandler func(username, password string) (userID string, err error)
 
 	// RefreshingScopeHandler check the scope of the refreshing token
-	RefreshingScopeHandler func(newScope, oldScope string) (allowed bool, err error)
+	RefreshingScopeHandler func(tgr *oauth2.TokenGenerateRequest, oldScope string) (allowed bool, err error)
 
-	//RefreshingValidationHandler check if refresh_token is still valid. eg no revocation or other
+	// RefreshingValidationHandler check if refresh_token is still valid. eg no revocation or other
 	RefreshingValidationHandler func(ti oauth2.TokenInfo) (allowed bool, err error)
 
 	// ResponseErrorHandler response error handing
diff --git a/vendor/github.com/go-oauth2/oauth2/v4/server/server.go b/vendor/github.com/go-oauth2/oauth2/v4/server/server.go
index 4e1215fc7..af911f429 100644
--- a/vendor/github.com/go-oauth2/oauth2/v4/server/server.go
+++ b/vendor/github.com/go-oauth2/oauth2/v4/server/server.go
@@ -214,7 +214,15 @@ func (s *Server) GetAuthorizeToken(ctx context.Context, req *AuthorizeRequest) (
 
 	// check the client allows the authorized scope
 	if fn := s.ClientScopeHandler; fn != nil {
-		allowed, err := fn(req.ClientID, req.Scope)
+		tgr := &oauth2.TokenGenerateRequest{
+			ClientID:       req.ClientID,
+			UserID:         req.UserID,
+			RedirectURI:    req.RedirectURI,
+			Scope:          req.Scope,
+			AccessTokenExp: req.AccessTokenExp,
+			Request:        req.Request,
+		}
+		allowed, err := fn(tgr)
 		if err != nil {
 			return nil, err
 		} else if !allowed {
@@ -311,11 +319,6 @@ func (s *Server) ValidationTokenRequest(r *http.Request) (oauth2.GrantType, *oau
 		return "", nil, errors.ErrUnsupportedGrantType
 	}
 
-	codeVer := r.FormValue("code_verifier")
-	if s.Config.ForcePKCE && codeVer == "" {
-		return "", nil, errors.ErrInvalidRequest
-	}
-
 	clientID, clientSecret, err := s.ClientInfoHandler(r)
 	if err != nil {
 		return "", nil, err
@@ -335,7 +338,10 @@ func (s *Server) ValidationTokenRequest(r *http.Request) (oauth2.GrantType, *oau
 			tgr.Code == "" {
 			return "", nil, errors.ErrInvalidRequest
 		}
-		tgr.CodeVerifier = codeVer
+		tgr.CodeVerifier = r.FormValue("code_verifier")
+		if s.Config.ForcePKCE && tgr.CodeVerifier == "" {
+			return "", nil, errors.ErrInvalidRequest
+		}
 	case oauth2.PasswordCredentials:
 		tgr.Scope = r.FormValue("scope")
 		username, password := r.FormValue("username"), r.FormValue("password")
@@ -404,7 +410,7 @@ func (s *Server) GetAccessToken(ctx context.Context, gt oauth2.GrantType, tgr *o
 		return ti, nil
 	case oauth2.PasswordCredentials, oauth2.ClientCredentials:
 		if fn := s.ClientScopeHandler; fn != nil {
-			allowed, err := fn(tgr.ClientID, tgr.Scope)
+			allowed, err := fn(tgr)
 			if err != nil {
 				return nil, err
 			} else if !allowed {
@@ -423,7 +429,7 @@ func (s *Server) GetAccessToken(ctx context.Context, gt oauth2.GrantType, tgr *o
 				return nil, err
 			}
 
-			allowed, err := scopeFn(scope, rti.GetScope())
+			allowed, err := scopeFn(tgr, rti.GetScope())
 			if err != nil {
 				return nil, err
 			} else if !allowed {
diff --git a/vendor/modules.txt b/vendor/modules.txt
index 9ca31ff24..ea21c488e 100644
--- a/vendor/modules.txt
+++ b/vendor/modules.txt
@@ -82,7 +82,7 @@ github.com/go-chi/httprate
 # github.com/go-chi/jwtauth v0.0.0-20190109153619-47840abb19b3
 ## explicit
 github.com/go-chi/jwtauth
-# github.com/go-oauth2/oauth2/v4 v4.2.0
+# github.com/go-oauth2/oauth2/v4 v4.3.0
 ## explicit
 github.com/go-oauth2/oauth2/v4
 github.com/go-oauth2/oauth2/v4/errors
@@ -212,8 +212,6 @@ github.com/prometheus/common/model
 # github.com/prometheus/procfs v0.0.0-20190507164030-5867b95ac084
 github.com/prometheus/procfs
 github.com/prometheus/procfs/internal/fs
-# github.com/quasoft/memstore v0.0.0-20191010062613-2bce066d2b0b
-## explicit
 # github.com/rwcarlsen/goexif v0.0.0-20190401172101-9e8deecbddbd
 ## explicit
 github.com/rwcarlsen/goexif/exif