diff --git a/ext/standard/browscap.c b/ext/standard/browscap.c
index 4fa766e3df8..d7b53e65993 100644
--- a/ext/standard/browscap.c
+++ b/ext/standard/browscap.c
@@ -228,7 +228,7 @@ static zend_string *browscap_intern_str(
 	} else {
 		interned = zend_string_copy(str);
 		if (persistent) {
-			interned = zend_new_interned_string(str);
+			interned = zend_new_interned_string(interned);
 		}
 		zend_hash_add_new_ptr(&ctx->str_interned, interned, interned);
 	}
@@ -397,10 +397,6 @@ static void php_browscap_parser_cb(zval *arg1, zval *arg2, zval *arg3, int callb
 }
 /* }}} */
 
-static void str_interned_dtor(zval *zv) {
-	zend_string_release(Z_STR_P(zv));
-}
-
 static int browscap_read_file(char *filename, browser_data *browdata, int persistent) /* {{{ */
 {
 	zend_file_handle fh;
@@ -430,7 +426,9 @@ static int browscap_read_file(char *filename, browser_data *browdata, int persis
 	ctx.bdata = browdata;
 	ctx.current_entry = NULL;
 	ctx.current_section_name = NULL;
-	zend_hash_init(&ctx.str_interned, 8, NULL, str_interned_dtor, persistent);
+	/* No dtor because we don't inc the refcount for the reference stored within the hash table's entry value
+	 * as the hash table is only temporary anyway. */
+	zend_hash_init(&ctx.str_interned, 8, NULL, NULL, persistent);
 
 	zend_parse_ini_file(&fh, persistent, ZEND_INI_SCANNER_RAW,
 			(zend_ini_parser_cb_t) php_browscap_parser_cb, &ctx);
diff --git a/sapi/fpm/tests/gh12621.phpt b/sapi/fpm/tests/gh12621.phpt
new file mode 100644
index 00000000000..0ee64fbe415
--- /dev/null
+++ b/sapi/fpm/tests/gh12621.phpt
@@ -0,0 +1,46 @@
+--TEST--
+GH-12621 (browscap segmentation fault when configured with php_admin_value)
+--SKIPIF--
+<?php include "skipif.inc"; ?>
+--FILE--
+<?php
+
+require_once "tester.inc";
+
+$cfg = <<<EOT
+[global]
+error_log = {{FILE:LOG}}
+[unconfined]
+listen = {{ADDR}}
+pm = dynamic
+pm.max_children = 5
+pm.start_servers = 1
+pm.min_spare_servers = 1
+pm.max_spare_servers = 3
+
+EOT;
+$cfg .= 'php_admin_value[browscap] = ' . __DIR__ . '/../../../ext/standard/tests/misc/browscap.ini';
+
+$code = <<<EOT
+<?php
+\$cv = get_browser("Konqueror/2.0")->browser_name_pattern;
+var_dump(\$cv);
+EOT;
+
+$tester = new FPM\Tester($cfg, $code);
+$tester->start();
+$tester->expectLogStartNotices();
+echo $tester
+    ->request()
+    ->getBody();
+$tester->terminate();
+$tester->close();
+
+?>
+--EXPECT--
+string(14) "*Konqueror/2.*"
+--CLEAN--
+<?php
+require_once "tester.inc";
+FPM\Tester::clean();
+?>