diff --git a/exec.go b/exec.go
index 18c6bffde..cdc9859ca 100644
--- a/exec.go
+++ b/exec.go
@@ -162,7 +162,10 @@ func execProcess(context *cli.Context) (int, error) {
 	if err != nil {
 		return -1, err
 	}
-	bundle := utils.SearchLabels(state.Config.Labels, "bundle")
+	bundle, ok := utils.SearchLabels(state.Config.Labels, "bundle")
+	if !ok {
+		return -1, errors.New("bundle not found in labels")
+	}
 	p, err := getProcess(context, bundle)
 	if err != nil {
 		return -1, err
diff --git a/libcontainer/utils/utils.go b/libcontainer/utils/utils.go
index 6b9fc3435..dbd435341 100644
--- a/libcontainer/utils/utils.go
+++ b/libcontainer/utils/utils.go
@@ -132,19 +132,16 @@ func WithProcfd(root, unsafePath string, fn func(procfd string) error) error {
 	return fn(procfd)
 }
 
-// SearchLabels searches a list of key-value pairs for the provided key and
-// returns the corresponding value. The pairs must be separated with '='.
-func SearchLabels(labels []string, query string) string {
-	for _, l := range labels {
-		parts := strings.SplitN(l, "=", 2)
-		if len(parts) < 2 {
-			continue
-		}
-		if parts[0] == query {
-			return parts[1]
+// SearchLabels searches through a list of key=value pairs for a given key,
+// returning its value, and the binary flag telling whether the key exist.
+func SearchLabels(labels []string, key string) (string, bool) {
+	key += "="
+	for _, s := range labels {
+		if strings.HasPrefix(s, key) {
+			return s[len(key):], true
 		}
 	}
-	return ""
+	return "", false
 }
 
 // Annotations returns the bundle path and user defined annotations from the
diff --git a/libcontainer/utils/utils_test.go b/libcontainer/utils/utils_test.go
index 52fc93639..06c042f5f 100644
--- a/libcontainer/utils/utils_test.go
+++ b/libcontainer/utils/utils_test.go
@@ -8,22 +8,28 @@ import (
 )
 
 var labelTest = []struct {
-	labels        []string
-	query         string
-	expectedValue string
+	labels []string
+	query  string
+	expVal string
+	expOk  bool
 }{
-	{[]string{"bundle=/path/to/bundle"}, "bundle", "/path/to/bundle"},
-	{[]string{"test=a", "test=b"}, "bundle", ""},
-	{[]string{"bundle=a", "test=b", "bundle=c"}, "bundle", "a"},
-	{[]string{"", "test=a", "bundle=b"}, "bundle", "b"},
-	{[]string{"test", "bundle=a"}, "bundle", "a"},
-	{[]string{"test=a", "bundle="}, "bundle", ""},
+	{[]string{"bundle=/path/to/bundle"}, "bundle", "/path/to/bundle", true},
+	{[]string{"test=a", "test=b"}, "bundle", "", false},
+	{[]string{"bundle=a", "test=b", "bundle=c"}, "bundle", "a", true},
+	{[]string{"", "test=a", "bundle=b"}, "bundle", "b", true},
+	{[]string{"test", "bundle=a"}, "bundle", "a", true},
+	{[]string{"test=a", "bundle="}, "bundle", "", true},
 }
 
 func TestSearchLabels(t *testing.T) {
 	for _, tt := range labelTest {
-		if v := SearchLabels(tt.labels, tt.query); v != tt.expectedValue {
-			t.Errorf("expected value '%s' for query '%s'; got '%s'", tt.expectedValue, tt.query, v)
+		v, ok := SearchLabels(tt.labels, tt.query)
+		if ok != tt.expOk {
+			t.Errorf("expected ok: %v, got %v", tt.expOk, ok)
+			continue
+		}
+		if v != tt.expVal {
+			t.Errorf("expected value '%s' for query '%s'; got '%s'", tt.expVal, tt.query, v)
 		}
 	}
 }