diff --git a/ext/fileinfo/config.m4 b/ext/fileinfo/config.m4
index 346061411e08..2d6139f06dff 100644
--- a/ext/fileinfo/config.m4
+++ b/ext/fileinfo/config.m4
@@ -29,11 +29,6 @@ if test "$PHP_FILEINFO" != "no"; then
 
   AC_CHECK_HEADERS([sys/sysmacros.h])
 
-  AC_CHECK_FUNCS([strcasestr],,[
-    AC_MSG_NOTICE([using libmagic strcasestr implementation])
-    libmagic_sources="$libmagic_sources libmagic/strcasestr.c"
-  ])
-
   AX_GCC_FUNC_ATTRIBUTE([visibility])
 
   PHP_NEW_EXTENSION([fileinfo],
diff --git a/ext/fileinfo/config.w32 b/ext/fileinfo/config.w32
index 2a42dc45a1d1..34670e7451e4 100644
--- a/ext/fileinfo/config.w32
+++ b/ext/fileinfo/config.w32
@@ -8,7 +8,7 @@ if (PHP_FILEINFO != 'no') {
 			encoding.c fsmagic.c funcs.c \
 			is_json.c is_tar.c is_simh.c magic.c print.c \
 			readcdf.c softmagic.c der.c \
-			strcasestr.c buffer.c is_csv.c";
+			buffer.c is_csv.c";
 
 	EXTENSION('fileinfo', 'fileinfo.c php_libmagic.c', true, "/I" + configure_module_dirname + "/libmagic /I" + configure_module_dirname);
 	ADD_EXTENSION_DEP('fileinfo', 'pcre');
diff --git a/ext/fileinfo/libmagic.patch b/ext/fileinfo/libmagic.patch
index d2db3c044d3f..6e3751fa943f 100644
--- a/ext/fileinfo/libmagic.patch
+++ b/ext/fileinfo/libmagic.patch
@@ -1727,7 +1727,7 @@ diff -u libmagic.orig/encoding.c libmagic/encoding.c
  }
 diff -u libmagic.orig/file.h libmagic/file.h
 --- libmagic.orig/file.h	2024-11-27 10:37:00.000000000 -0500
-+++ libmagic/file.h	2026-03-24 10:45:21.427536159 -0400
++++ libmagic/file.h	2026-03-25 08:13:23.336328498 -0400
 @@ -27,15 +27,13 @@
   */
  /*
@@ -1883,7 +1883,7 @@ diff -u libmagic.orig/file.h libmagic/file.h
  typedef struct {
  	char *buf;
  	size_t blen;
-@@ -649,19 +629,6 @@
+@@ -649,28 +629,12 @@
  extern file_protected const size_t file_nnames;
  #endif
  
@@ -1903,7 +1903,16 @@ diff -u libmagic.orig/file.h libmagic/file.h
  #ifndef HAVE_STRLCPY
  size_t strlcpy(char *, const char *, size_t);
  #endif
-@@ -681,31 +648,6 @@
+ #ifndef HAVE_STRLCAT
+ size_t strlcat(char *, const char *, size_t);
+ #endif
+-#ifndef HAVE_STRCASESTR
+-char *strcasestr(const char *, const char *);
+-#endif
+ #ifndef HAVE_GETLINE
+ ssize_t getline(char **, size_t *, FILE *);
+ ssize_t getdelim(char **, size_t *, int, FILE *);
+@@ -681,31 +645,6 @@
  #ifndef HAVE_ASCTIME_R
  char   *asctime_r(const struct tm *, char *);
  #endif
@@ -3066,7 +3075,7 @@ diff -u libmagic.orig/magic.c libmagic/magic.c
  	}
  	return file_getbuffer(ms);
 diff -u libmagic.orig/magic.h libmagic/magic.h
---- libmagic.orig/magic.h	2026-03-24 10:45:56.975553410 -0400
+--- libmagic.orig/magic.h	2026-03-25 08:16:04.280413419 -0400
 +++ libmagic/magic.h	2026-03-20 12:10:19.777614667 -0400
 @@ -47,8 +47,6 @@
  					   * extensions */
diff --git a/ext/fileinfo/libmagic/file.h b/ext/fileinfo/libmagic/file.h
index f8fe58895002..718a60b2e1b0 100644
--- a/ext/fileinfo/libmagic/file.h
+++ b/ext/fileinfo/libmagic/file.h
@@ -635,9 +635,6 @@ size_t strlcpy(char *, const char *, size_t);
 #ifndef HAVE_STRLCAT
 size_t strlcat(char *, const char *, size_t);
 #endif
-#ifndef HAVE_STRCASESTR
-char *strcasestr(const char *, const char *);
-#endif
 #ifndef HAVE_GETLINE
 ssize_t getline(char **, size_t *, FILE *);
 ssize_t getdelim(char **, size_t *, int, FILE *);
diff --git a/ext/spl/php_spl.c b/ext/spl/php_spl.c
index e705a1e303a2..0c64d815dc81 100644
--- a/ext/spl/php_spl.c
+++ b/ext/spl/php_spl.c
@@ -64,7 +64,7 @@ static zend_class_entry * spl_find_ce_by_name(zend_string *name, bool autoload)
 PHP_FUNCTION(class_parents)
 {
 	zval *obj;
-	zend_class_entry *parent_class, *ce;
+	zend_class_entry *ce;
 	bool autoload = true;
 
 	/* We do not use Z_PARAM_OBJ_OR_STR here to be able to exclude int, float, and bool which are bogus class names */
@@ -86,7 +86,7 @@ PHP_FUNCTION(class_parents)
 	}
 
 	array_init(return_value);
-	parent_class = ce->parent;
+	const zend_class_entry *parent_class = ce->parent;
 	while (parent_class) {
 		spl_add_class_name(return_value, parent_class, 0, 0);
 		parent_class = parent_class->parent;
@@ -99,7 +99,7 @@ PHP_FUNCTION(class_implements)
 {
 	zval *obj;
 	bool autoload = true;
-	zend_class_entry *ce;
+	const zend_class_entry *ce;
 
 	/* We do not use Z_PARAM_OBJ_OR_STR here to be able to exclude int, float, and bool which are bogus class names */
 	if (zend_parse_parameters(ZEND_NUM_ARGS(), "z|b", &obj, &autoload) == FAILURE) {
@@ -128,7 +128,7 @@ PHP_FUNCTION(class_uses)
 {
 	zval *obj;
 	bool autoload = true;
-	zend_class_entry *ce;
+	const zend_class_entry *ce;
 
 	/* We do not use Z_PARAM_OBJ_OR_STR here to be able to exclude int, float, and bool which are bogus class names */
 	if (zend_parse_parameters(ZEND_NUM_ARGS(), "z|b", &obj, &autoload) == FAILURE) {
diff --git a/ext/spl/spl_array.c b/ext/spl/spl_array.c
index 3d6870a7ee95..efbe331104ab 100644
--- a/ext/spl/spl_array.c
+++ b/ext/spl/spl_array.c
@@ -157,7 +157,7 @@ static void spl_array_object_free_storage(zend_object *object)
 static zend_object *spl_array_object_new_ex(zend_class_entry *class_type, zend_object *orig, int clone_orig)
 {
 	spl_array_object *intern;
-	zend_class_entry *parent = class_type;
+	const zend_class_entry *parent = class_type;
 	int inherited = 0;
 
 	intern = zend_object_alloc(sizeof(spl_array_object), parent);
diff --git a/ext/spl/spl_dllist.c b/ext/spl/spl_dllist.c
index 5eceff88dfab..c72cae38a9ce 100644
--- a/ext/spl/spl_dllist.c
+++ b/ext/spl/spl_dllist.c
@@ -304,7 +304,7 @@ static void spl_dllist_object_free_storage(zend_object *object) /* {{{ */
 static zend_object *spl_dllist_object_new_ex(zend_class_entry *class_type, zend_object *orig, int clone_orig) /* {{{ */
 {
 	spl_dllist_object *intern;
-	zend_class_entry  *parent = class_type;
+	const zend_class_entry *parent = class_type;
 	int                inherited = 0;
 
 	intern = zend_object_alloc(sizeof(spl_dllist_object), parent);
@@ -316,7 +316,7 @@ static zend_object *spl_dllist_object_new_ex(zend_class_entry *class_type, zend_
 	intern->traverse_position = 0;
 
 	if (orig) {
-		spl_dllist_object *other = spl_dllist_from_obj(orig);
+		const spl_dllist_object *other = spl_dllist_from_obj(orig);
 
 		if (clone_orig) {
 			intern->llist = spl_ptr_llist_init();
diff --git a/ext/spl/spl_functions.c b/ext/spl/spl_functions.c
index e7ecbc33f92e..7b7991a12170 100644
--- a/ext/spl/spl_functions.c
+++ b/ext/spl/spl_functions.c
@@ -21,12 +21,12 @@
 #include "php.h"
 
 /* {{{ spl_add_class_name */
-void spl_add_class_name(zval *list, zend_class_entry *pce, int allow, int ce_flags)
+void spl_add_class_name(zval *list, const zend_class_entry *pce, int allow, int ce_flags)
 {
 	if (!allow || (allow > 0 && (pce->ce_flags & ce_flags)) || (allow < 0 && !(pce->ce_flags & ce_flags))) {
-		zval *tmp;
+		const zval *tmp = zend_hash_find(Z_ARRVAL_P(list), pce->name);
 
-		if ((tmp = zend_hash_find(Z_ARRVAL_P(list), pce->name)) == NULL) {
+		if (tmp == NULL) {
 			zval t;
 			ZVAL_STR_COPY(&t, pce->name);
 			zend_hash_add(Z_ARRVAL_P(list), pce->name, &t);
@@ -36,7 +36,7 @@ void spl_add_class_name(zval *list, zend_class_entry *pce, int allow, int ce_fla
 /* }}} */
 
 /* {{{ spl_add_interfaces */
-void spl_add_interfaces(zval *list, zend_class_entry * pce, int allow, int ce_flags)
+void spl_add_interfaces(zval *list, const zend_class_entry *pce, int allow, int ce_flags)
 {
 	if (pce->num_interfaces) {
 		ZEND_ASSERT(pce->ce_flags & ZEND_ACC_LINKED);
@@ -48,12 +48,10 @@ void spl_add_interfaces(zval *list, zend_class_entry * pce, int allow, int ce_fl
 /* }}} */
 
 /* {{{ spl_add_traits */
-void spl_add_traits(zval *list, zend_class_entry * pce, int allow, int ce_flags)
+void spl_add_traits(zval *list, const zend_class_entry *pce, int allow, int ce_flags)
 {
-	zend_class_entry *trait;
-
 	for (uint32_t num_traits = 0; num_traits < pce->num_traits; num_traits++) {
-		trait = zend_fetch_class_by_name(pce->trait_names[num_traits].name,
+		const zend_class_entry *trait = zend_fetch_class_by_name(pce->trait_names[num_traits].name,
 			pce->trait_names[num_traits].lc_name, ZEND_FETCH_CLASS_TRAIT);
 		ZEND_ASSERT(trait);
 		spl_add_class_name(list, trait, allow, ce_flags);
@@ -63,7 +61,7 @@ void spl_add_traits(zval *list, zend_class_entry * pce, int allow, int ce_flags)
 
 
 /* {{{ spl_add_classes */
-void spl_add_classes(zend_class_entry *pce, zval *list, bool sub, int allow, int ce_flags)
+void spl_add_classes(const zend_class_entry *pce, zval *list, bool sub, int allow, int ce_flags)
 {
 	ZEND_ASSERT(pce);
 	spl_add_class_name(list, pce, allow, ce_flags);
diff --git a/ext/spl/spl_functions.h b/ext/spl/spl_functions.h
index eb81a8b8f818..ca92a237169e 100644
--- a/ext/spl/spl_functions.h
+++ b/ext/spl/spl_functions.h
@@ -24,10 +24,10 @@
    allow > 0: allow all that match and mask ce_flags
    allow < 0: disallow all that match and mask ce_flags
  */
-void spl_add_class_name(zval * list, zend_class_entry * pce, int allow, int ce_flags);
-void spl_add_interfaces(zval * list, zend_class_entry * pce, int allow, int ce_flags);
-void spl_add_traits(zval * list, zend_class_entry * pce, int allow, int ce_flags);
-void spl_add_classes(zend_class_entry *pce, zval *list, bool sub, int allow, int ce_flags);
+void spl_add_class_name(zval * list, const zend_class_entry *pce, int allow, int ce_flags);
+void spl_add_interfaces(zval * list, const zend_class_entry *pce, int allow, int ce_flags);
+void spl_add_traits(zval * list, const zend_class_entry *pce, int allow, int ce_flags);
+void spl_add_classes(const zend_class_entry *pce, zval *list, bool sub, int allow, int ce_flags);
 
 void spl_set_private_debug_info_property(const zend_class_entry *ce, const char *property, size_t property_len, HashTable *debug_info, zval *value);
 
diff --git a/ext/spl/spl_heap.c b/ext/spl/spl_heap.c
index afe3489e8984..eef25b9e3593 100644
--- a/ext/spl/spl_heap.c
+++ b/ext/spl/spl_heap.c
@@ -412,7 +412,7 @@ static void spl_heap_object_free_storage(zend_object *object) /* {{{ */
 static zend_object *spl_heap_object_new_ex(zend_class_entry *class_type, zend_object *orig, int clone_orig) /* {{{ */
 {
 	spl_heap_object   *intern;
-	zend_class_entry  *parent = class_type;
+	const zend_class_entry  *parent = class_type;
 	int                inherited = 0;
 
 	intern = zend_object_alloc(sizeof(spl_heap_object), parent);
diff --git a/ext/spl/spl_observer.c b/ext/spl/spl_observer.c
index 801c091fbb42..68f132069a7c 100644
--- a/ext/spl/spl_observer.c
+++ b/ext/spl/spl_observer.c
@@ -257,7 +257,7 @@ static void spl_object_storage_addall(spl_SplObjectStorage *intern, spl_SplObjec
 static zend_object *spl_object_storage_new_ex(zend_class_entry *class_type, zend_object *orig) /* {{{ */
 {
 	spl_SplObjectStorage *intern;
-	zend_class_entry *parent = class_type;
+	const zend_class_entry *parent = class_type;
 
 	intern = zend_object_alloc(sizeof(spl_SplObjectStorage), parent);
 	intern->pos = 0;