--- a/crt/aws-c-cal/source/der.c	2025-08-29 10:43:04.487705098 +0100
+++ B/crt/aws-c-cal/source/der.c	2025-08-29 14:27:00.649373755 +0100
@@ -80,21 +80,28 @@
     if (len_bytes & 0x80) {
         len_bytes &= 0x7f;
         switch (len_bytes) {
-            case 1:
-                if (!aws_byte_cursor_read_u8(cur, (uint8_t *)&len)) {
+            case 1: {
+                uint8_t len8;
+                if (!aws_byte_cursor_read_u8(cur, &len8)) {
                     return aws_raise_error(AWS_ERROR_CAL_MALFORMED_ASN1_ENCOUNTERED);
                 }
+                len = len8;
                 break;
-            case 2:
-                if (!aws_byte_cursor_read_be16(cur, (uint16_t *)&len)) {
+            }
+            case 2: {
+                uint16_t len16;
+                if (!aws_byte_cursor_read_be16(cur, &len16)) {
                     return aws_raise_error(AWS_ERROR_CAL_MALFORMED_ASN1_ENCOUNTERED);
                 }
+                len = len16;
                 break;
-            case 4:
+            }
+            case 4: {
                 if (!aws_byte_cursor_read_be32(cur, &len)) {
                     return aws_raise_error(AWS_ERROR_CAL_MALFORMED_ASN1_ENCOUNTERED);
                 }
                 break;
+            }
             default:
                 return aws_raise_error(AWS_ERROR_CAL_MALFORMED_ASN1_ENCOUNTERED);
         }