diff --git a/pkg/apiserver/schema/cel/compilation.go b/pkg/apiserver/schema/cel/compilation.go
index 4f065a18f..07ba73105 100644
--- a/pkg/apiserver/schema/cel/compilation.go
+++ b/pkg/apiserver/schema/cel/compilation.go
@@ -17,6 +17,7 @@ limitations under the License.
 package cel
 
 import (
+	"errors"
 	"fmt"
 	"strings"
 	"time"
@@ -125,6 +126,9 @@ func Compile(s *schema.Structural, declType *apiservercel.DeclType, perCallLimit
 	if len(s.Extensions.XValidations) == 0 {
 		return nil, nil
 	}
+	if declType == nil {
+		return nil, errors.New("failed to convert to declType for CEL validation rules")
+	}
 	celRules := s.Extensions.XValidations
 
 	oldSelfEnvSet, optionalOldSelfEnvSet, err := prepareEnvSet(baseEnvSet, declType)
diff --git a/pkg/apiserver/schema/cel/model/adaptor.go b/pkg/apiserver/schema/cel/model/adaptor.go
index 0bc109a73..aeed2a858 100644
--- a/pkg/apiserver/schema/cel/model/adaptor.go
+++ b/pkg/apiserver/schema/cel/model/adaptor.go
@@ -62,6 +62,9 @@ func (s *Structural) Pattern() string {
 }
 
 func (s *Structural) Items() common.Schema {
+	if s.Structural.Items == nil {
+		return nil
+	}
 	return &Structural{Structural: s.Structural.Items}
 }
 
diff --git a/pkg/apiserver/schema/cel/model/schemas_test.go b/pkg/apiserver/schema/cel/model/schemas_test.go
index 04ae3a1a4..f43f3e908 100644
--- a/pkg/apiserver/schema/cel/model/schemas_test.go
+++ b/pkg/apiserver/schema/cel/model/schemas_test.go
@@ -274,6 +274,7 @@ func TestEstimateMaxLengthJSON(t *testing.T) {
 		Name                string
 		InputSchema         *schema.Structural
 		ExpectedMaxElements int64
+		ExpectNilType       bool
 	}
 	tests := []maxLengthTest{
 		{
@@ -499,13 +500,61 @@ func TestEstimateMaxLengthJSON(t *testing.T) {
 			// so we expect the max length to be exactly equal to the user-supplied one
 			ExpectedMaxElements: 20,
 		},
+		{
+			Name: "Property under array",
+			InputSchema: &schema.Structural{
+				Generic: schema.Generic{
+					Type: "array",
+				},
+				Properties: map[string]schema.Structural{
+					"field": {
+						Generic: schema.Generic{
+							Type:    "string",
+							Default: schema.JSON{Object: "default"},
+						},
+					},
+				},
+			},
+			// Got nil for delType
+			ExpectedMaxElements: 0,
+			ExpectNilType:       true,
+		},
+		{
+			Name: "Items under object",
+			InputSchema: &schema.Structural{
+				Generic: schema.Generic{
+					Type: "object",
+				},
+				Items: &schema.Structural{
+					Generic: schema.Generic{
+						Type: "array",
+					},
+					Properties: map[string]schema.Structural{
+						"field": {
+							Generic: schema.Generic{
+								Type:    "string",
+								Default: schema.JSON{Object: "default"},
+							},
+						},
+					},
+					ValueValidation: &schema.ValueValidation{
+						Required: []string{"field"},
+					},
+				},
+			},
+			// Skip items under object for schema conversion.
+			ExpectedMaxElements: 0,
+		},
 	}
 	for _, testCase := range tests {
 		t.Run(testCase.Name, func(t *testing.T) {
 			decl := SchemaDeclType(testCase.InputSchema, false)
-			if decl.MaxElements != testCase.ExpectedMaxElements {
+			if decl != nil && decl.MaxElements != testCase.ExpectedMaxElements {
 				t.Errorf("wrong maxElements (got %d, expected %d)", decl.MaxElements, testCase.ExpectedMaxElements)
 			}
+			if testCase.ExpectNilType && decl != nil {
+				t.Errorf("expected nil type, got %v", decl)
+			}
 		})
 	}
 }
diff --git a/pkg/apiserver/schema/cel/validation.go b/pkg/apiserver/schema/cel/validation.go
index d9b595805..835f13eb5 100644
--- a/pkg/apiserver/schema/cel/validation.go
+++ b/pkg/apiserver/schema/cel/validation.go
@@ -94,8 +94,14 @@ func validator(s *schema.Structural, isResourceRoot bool, declType *cel.DeclType
 	compiledRules, err := Compile(s, declType, perCallLimit, environment.MustBaseEnvSet(environment.DefaultCompatibilityVersion(), true), StoredExpressionsEnvLoader())
 	var itemsValidator, additionalPropertiesValidator *Validator
 	var propertiesValidators map[string]Validator
+	var elemType *cel.DeclType
+	if declType != nil {
+		elemType = declType.ElemType
+	} else {
+		elemType = declType
+	}
 	if s.Items != nil {
-		itemsValidator = validator(s.Items, s.Items.XEmbeddedResource, declType.ElemType, perCallLimit)
+		itemsValidator = validator(s.Items, s.Items.XEmbeddedResource, elemType, perCallLimit)
 	}
 	if len(s.Properties) > 0 {
 		propertiesValidators = make(map[string]Validator, len(s.Properties))
@@ -103,6 +109,9 @@ func validator(s *schema.Structural, isResourceRoot bool, declType *cel.DeclType
 			prop := p
 			var fieldType *cel.DeclType
 			if escapedPropName, ok := cel.Escape(k); ok {
+				if declType == nil {
+					continue
+				}
 				if f, ok := declType.Fields[escapedPropName]; ok {
 					fieldType = f.Type
 				} else {
@@ -123,7 +132,7 @@ func validator(s *schema.Structural, isResourceRoot bool, declType *cel.DeclType
 		}
 	}
 	if s.AdditionalProperties != nil && s.AdditionalProperties.Structural != nil {
-		additionalPropertiesValidator = validator(s.AdditionalProperties.Structural, s.AdditionalProperties.Structural.XEmbeddedResource, declType.ElemType, perCallLimit)
+		additionalPropertiesValidator = validator(s.AdditionalProperties.Structural, s.AdditionalProperties.Structural.XEmbeddedResource, elemType, perCallLimit)
 	}
 	if len(compiledRules) > 0 || err != nil || itemsValidator != nil || additionalPropertiesValidator != nil || len(propertiesValidators) > 0 {
 		activationFactory := validationActivationWithoutOldSelf