diff --git a/builtin/logical/pki/path_root.go b/builtin/logical/pki/path_root.go
index fc5476bef0..db2b4cd0d4 100644
--- a/builtin/logical/pki/path_root.go
+++ b/builtin/logical/pki/path_root.go
@@ -334,9 +334,7 @@ func (b *backend) pathIssuerSignIntermediate(ctx context.Context, req *logical.R
 
 	format := getFormat(data)
 	if format == "" {
-		return logical.ErrorResponse(
-			`The "format" path parameter must be "pem" or "der"`,
-		), nil
+		return logical.ErrorResponse(`The "format" path parameter must be "pem", "der" or "pem_bundle"`), nil
 	}
 
 	role := &roleEntry{
@@ -416,6 +414,26 @@ func (b *backend) pathIssuerSignIntermediate(ctx context.Context, req *logical.R
 		return nil, fmt.Errorf("verification of parsed bundle failed: %w", err)
 	}
 
+	resp, err := signIntermediateResponse(signingBundle, parsedBundle, format, warnings)
+	if err != nil {
+		return nil, err
+	}
+
+	key := "certs/" + normalizeSerialFromBigInt(parsedBundle.Certificate.SerialNumber)
+	certsCounted := b.certsCounted.Load()
+	err = req.Storage.Put(ctx, &logical.StorageEntry{
+		Key:   key,
+		Value: parsedBundle.CertificateBytes,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("unable to store certificate locally: %w", err)
+	}
+	b.ifCountEnabledIncrementTotalCertificatesCount(certsCounted, key)
+
+	return resp, nil
+}
+
+func signIntermediateResponse(signingBundle *certutil.CAInfoBundle, parsedBundle *certutil.ParsedCertBundle, format string, warnings []string) (*logical.Response, error) {
 	signingCB, err := signingBundle.ToCertBundle()
 	if err != nil {
 		return nil, fmt.Errorf("error converting raw signing bundle to cert bundle: %w", err)
@@ -485,23 +503,11 @@ func (b *backend) pathIssuerSignIntermediate(ctx context.Context, req *logical.R
 		return nil, fmt.Errorf("unsupported format argument: %s", format)
 	}
 
-	key := "certs/" + normalizeSerial(cb.SerialNumber)
-	certsCounted := b.certsCounted.Load()
-	err = req.Storage.Put(ctx, &logical.StorageEntry{
-		Key:   key,
-		Value: parsedBundle.CertificateBytes,
-	})
-	if err != nil {
-		return nil, fmt.Errorf("unable to store certificate locally: %w", err)
-	}
-	b.ifCountEnabledIncrementTotalCertificatesCount(certsCounted, key)
-
 	if parsedBundle.Certificate.MaxPathLen == 0 {
 		resp.AddWarning("Max path length of the signed certificate is zero. This certificate cannot be used to issue intermediate CA certificates.")
 	}
 
 	resp = addWarnings(resp, warnings)
-
 	return resp, nil
 }
 
diff --git a/builtin/logical/pki/path_sign_issuers.go b/builtin/logical/pki/path_sign_issuers.go
index 0b6b8334e4..ff9bdd0ef0 100644
--- a/builtin/logical/pki/path_sign_issuers.go
+++ b/builtin/logical/pki/path_sign_issuers.go
@@ -55,7 +55,7 @@ func buildPathIssuerSignIntermediateRaw(b *backend, pattern string, displayAttrs
 							"serial_number": {
 								Type:        framework.TypeString,
 								Description: `Serial Number`,
-								Required:    false,
+								Required:    true,
 							},
 							"certificate": {
 								Type:        framework.TypeString,
diff --git a/sdk/helper/certutil/cieps.go b/sdk/helper/certutil/cieps.go
index ac5d145e4d..382a4c20cf 100644
--- a/sdk/helper/certutil/cieps.go
+++ b/sdk/helper/certutil/cieps.go
@@ -22,7 +22,7 @@ const (
 	SignCIEPSMode  = "sign"
 	IssueCIEPSMode = "issue"
 	ACMECIEPSMode  = "acme"
-	ICACIEPSMOde   = "ica"
+	ICACIEPSMode   = "ica"
 )
 
 // Configuration of the issuer and mount at the time of this request;