diff --git a/CHANGELOG.md b/CHANGELOG.md
index 86b41417e..fe5b226c0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -25,6 +25,7 @@ Unreleased changes are available as `avenga/couper:edge` container.
   * possible race conditions while updating JWKS for the [JWT access control](./docs/REFERENCE.md#jwt-block) ([#398](https://github.com/avenga/couper/pull/398))
   * panic while accessing primitive variables with a key ([#377](https://github.com/avenga/couper/issues/377))
   * [`default()`](./docs/REFERENCE.md#functions) function continues to their fallback value if this is a string type and an argument evaluates to an empty string ([#408](https://github.com/avenga/couper/issues/408))
+  * missing read of client-request bodies if related variables are used in referenced access controls only (e.g. jwt token source) ([#415](https://github.com/avenga/couper/pull/415))
 
 * **Dependencies**
   * Update modules for [OpenAPI](./docs/REFERENCE.md#openapi-block) validation ([#399](https://github.com/avenga/couper/pull/399))
diff --git a/config/runtime/server.go b/config/runtime/server.go
index 7d1c85226..0d66c0aeb 100644
--- a/config/runtime/server.go
+++ b/config/runtime/server.go
@@ -259,6 +259,13 @@ func NewServerConfiguration(conf *config.Couper, log *logrus.Entry, memStore *ca
 				return nil, err
 			}
 
+			// Evaluate access-control related buffer options.
+			acBodies := bodiesWithACBodies(conf.Definitions,
+				newAC(srvConf, parentAPI).
+					Merge(config.
+						NewAccessControl(endpointConf.AccessControl, endpointConf.DisableAccessControl)).List(), nil)
+			epOpts.BufferOpts |= eval.MustBuffer(acBodies...)
+
 			errorHandlerDefinitions := ACDefinitions{ // misuse of definitions obj for now
 				"endpoint": &AccessControl{ErrorHandler: endpointConf.ErrorHandler},
 			}
diff --git a/eval/buffer.go b/eval/buffer.go
index acea211c2..c0e41d8dc 100644
--- a/eval/buffer.go
+++ b/eval/buffer.go
@@ -37,7 +37,7 @@ func (i BufferOption) Response() bool {
 }
 
 // MustBuffer determines if any of the hcl.bodies makes use of 'body', 'form_body' or 'json_body' or
-// of known attributes and variables which requires a parsed client-request body.
+// of known attributes and variables which require a parsed client-request or backend-response body.
 func MustBuffer(bodies ...hcl.Body) BufferOption {
 	result := BufferNone
 
diff --git a/server/http_endpoints_test.go b/server/http_endpoints_test.go
index 36384d143..e8853ec75 100644
--- a/server/http_endpoints_test.go
+++ b/server/http_endpoints_test.go
@@ -9,6 +9,7 @@ import (
 	"io"
 	"net/http"
 	"net/http/httptest"
+	"net/url"
 	"path/filepath"
 	"reflect"
 	"strconv"
@@ -757,3 +758,79 @@ func TestEndpointErrorHandler(t *testing.T) {
 		})
 	}
 }
+
+func TestEndpointACBufferOptions(t *testing.T) {
+	client := test.NewHTTPClient()
+	helper := test.New(t)
+
+	shutdown, hook := newCouper(filepath.Join(testdataPath, "17_couper.hcl"), helper)
+	defer shutdown()
+
+	invalidToken := "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ.p_L2kBaXuGvD2AhW5WEheAKLErYXPDR-LKj_dZ5G_XI"
+	validToken := "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ.6M2CwQMZ-PkeSyREi5scviq0EilhUUSgax6W9TmxmS8"
+
+	urlencoded := func(token string) string {
+		return url.Values{"token": []string{token}}.Encode()
+	}
+	json := func(token string) string {
+		return fmt.Sprintf("{%q: %q}", "token", token)
+	}
+	plain := func(token string) string {
+		return token
+	}
+
+	type testcase struct {
+		name              string
+		path              string
+		token             string
+		bodyFunc          func(string) string
+		contentType       string
+		expectedStatus    int
+		expectedErrorType string
+	}
+
+	for _, tc := range []testcase{
+		{"with ac (token in-form_body) and wrong token", "/in-form_body", invalidToken, urlencoded, "application/x-www-form-urlencoded", http.StatusForbidden, "jwt"},
+		{"with ac (token in-form_body) and without token", "/in-form_body", "", urlencoded, "application/x-www-form-urlencoded", http.StatusUnauthorized, "jwt_token_missing"},
+		{"with ac (token in-form_body) and valid token", "/in-form_body", validToken, urlencoded, "application/x-www-form-urlencoded", http.StatusOK, ""},
+		{"with ac (token in-json_body) and wrong token", "/in-json_body", invalidToken, json, "application/json", http.StatusForbidden, "jwt"},
+		{"with ac (token in-json_body) and without token", "/in-json_body", "", json, "application/json", http.StatusUnauthorized, "jwt_token_missing"},
+		{"with ac (token in-json_body) and valid token", "/in-json_body", validToken, json, "application/json", http.StatusOK, ""},
+		{"with ac (token in-body) and wrong token", "/in-body", invalidToken, plain, "text/plain", http.StatusForbidden, "jwt"},
+		{"with ac (token in-body) and without token", "/in-body", "", plain, "text/plain", http.StatusUnauthorized, "jwt_token_missing"},
+		{"with ac (token in-body) and valid token", "/in-body", validToken, plain, "text/plain", http.StatusOK, ""},
+		{"without ac", "/without-ac", "", nil, "text/plain", http.StatusOK, ""},
+	} {
+		t.Run(tc.name, func(st *testing.T) {
+			hook.Reset()
+			h := test.New(st)
+
+			body := ""
+			if tc.bodyFunc != nil {
+				body = tc.bodyFunc(tc.token)
+			}
+			req, err := http.NewRequest(http.MethodPost, "http://domain.local:8080"+tc.path, strings.NewReader(body))
+			h.Must(err)
+
+			req.Header.Set("Content-Type", tc.contentType)
+
+			res, err := client.Do(req)
+			h.Must(err)
+
+			if res.StatusCode != tc.expectedStatus {
+				st.Errorf("want: %d, got: %d", tc.expectedStatus, res.StatusCode)
+			}
+
+			if tc.expectedErrorType != "" {
+				for _, e := range hook.AllEntries() {
+					if e.Data["type"] != "couper_access" {
+						continue
+					}
+					if e.Data["error_type"] != tc.expectedErrorType {
+						st.Errorf("want: %q, got: %v", tc.expectedErrorType, e.Data["error_type"])
+					}
+				}
+			}
+		})
+	}
+}
diff --git a/server/testdata/endpoints/17_couper.hcl b/server/testdata/endpoints/17_couper.hcl
new file mode 100644
index 000000000..d2c7dd82a
--- /dev/null
+++ b/server/testdata/endpoints/17_couper.hcl
@@ -0,0 +1,48 @@
+server {
+  endpoint "/in-form_body" {
+    access_control = ["in-form_body"]
+    response {
+      body = request.url
+    }
+  }
+
+  endpoint "/in-json_body" {
+    access_control = ["in-json_body"]
+    response {
+      body = request.url
+    }
+  }
+
+  endpoint "/in-body" {
+    access_control = ["in-body"]
+    response {
+      body = request.url
+    }
+  }
+
+  endpoint "/without-ac" {
+    response {
+      body = request.url
+    }
+  }
+}
+
+definitions {
+  jwt "in-form_body" {
+    signature_algorithm = "HS256"
+    key = "test123"
+    token_value = request.form_body.token[0]
+  }
+
+  jwt "in-json_body" {
+    signature_algorithm = "HS256"
+    key = "test123"
+    token_value = request.json_body.token
+  }
+
+  jwt "in-body" {
+    signature_algorithm = "HS256"
+    key = "test123"
+    token_value = request.body
+  }
+}