diff --git a/UPGRADING b/UPGRADING
index b9cc1e2b80a..35e388b939f 100644
--- a/UPGRADING
+++ b/UPGRADING
@@ -471,6 +471,9 @@ PHP 8.1 UPGRADE NOTES
     accessible through reflection.
     RFC: https://wiki.php.net/rfc/make-reflection-setaccessible-no-op
 
+- Standard:
+  . syslog() is now binary safe.
+
 ========================================
 6. New Functions
 ========================================
diff --git a/ext/standard/syslog.c b/ext/standard/syslog.c
index ab7be9d5b96..d2cfcab9ded 100644
--- a/ext/standard/syslog.c
+++ b/ext/standard/syslog.c
@@ -174,15 +174,14 @@ PHP_FUNCTION(closelog)
 PHP_FUNCTION(syslog)
 {
 	zend_long priority;
-	char *message;
-	size_t message_len;
+	zend_string *message;
 
 	ZEND_PARSE_PARAMETERS_START(2, 2)
 		Z_PARAM_LONG(priority)
-		Z_PARAM_STRING(message, message_len)
+		Z_PARAM_STR(message)
 	ZEND_PARSE_PARAMETERS_END();
 
-	php_syslog(priority, "%s", message);
+	php_syslog_str(priority, message);
 	RETURN_TRUE;
 }
 /* }}} */
diff --git a/ext/standard/tests/network/syslog_new_line.phpt b/ext/standard/tests/network/syslog_new_line.phpt
new file mode 100644
index 00000000000..69eb9c1d67e
--- /dev/null
+++ b/ext/standard/tests/network/syslog_new_line.phpt
@@ -0,0 +1,19 @@
+--TEST--
+Test syslog() function : new line in message
+--SKIPIF--
+<?php
+if(substr(PHP_OS, 0, 3) == "WIN")
+  die("skip Won't run on Windows");
+?>
+--FILE--
+<?php
+$priority = LOG_WARNING;
+$message = "First line\nSecond line";
+
+openlog('PHPT', LOG_PERROR, LOG_USER);
+syslog($priority, $message);
+
+?>
+--EXPECTF--
+%SPHPT%S%r(:|-)%r First line
+%SPHPT%S%r(:|-)%r Second line
diff --git a/ext/standard/tests/network/syslog_null_byte.phpt b/ext/standard/tests/network/syslog_null_byte.phpt
new file mode 100644
index 00000000000..e7cb1fb7a4b
--- /dev/null
+++ b/ext/standard/tests/network/syslog_null_byte.phpt
@@ -0,0 +1,18 @@
+--TEST--
+Test syslog() function : nul byte in message
+--SKIPIF--
+<?php
+if(substr(PHP_OS, 0, 3) == "WIN")
+  die("skip Won't run on Windows");
+?>
+--FILE--
+<?php
+$priority = LOG_WARNING;
+$message = "A simple \0 message";
+
+openlog('PHPT', LOG_PERROR, LOG_USER);
+syslog($priority, $message);
+
+?>
+--EXPECTF--
+%SPHPT%S%r(:|-)%r A simple \x00 message
diff --git a/main/php_syslog.c b/main/php_syslog.c
index e51a6a8a04f..54d871c6aca 100644
--- a/main/php_syslog.c
+++ b/main/php_syslog.c
@@ -32,6 +32,45 @@
 #define syslog std_syslog
 #endif
 
+PHPAPI void php_syslog_str(int priority, const zend_string* message)
+{
+	smart_string sbuf = {0};
+
+	if (PG(syslog_filter) == PHP_SYSLOG_FILTER_RAW) {
+		/* Just send it directly to the syslog */
+		syslog(priority, "%s", ZSTR_VAL(message));
+		return;
+	}
+
+	/* We use < because we don't want the final NUL byte to be converted to '\x00' */
+	for (size_t i = 0; i < ZSTR_LEN(message); ++i) {
+		unsigned char c = ZSTR_VAL(message)[i];
+
+		/* check for NVT ASCII only unless test disabled */
+		if (((0x20 <= c) && (c <= 0x7e))) {
+			smart_string_appendc(&sbuf, c);
+		} else if ((c >= 0x80) && (PG(syslog_filter) != PHP_SYSLOG_FILTER_ASCII)) {
+			smart_string_appendc(&sbuf, c);
+		} else if (c == '\n') {
+			/* Smart string is not NUL terminated */
+			syslog(priority, "%.*s", (int)sbuf.len, sbuf.c);
+			smart_string_reset(&sbuf);
+		} else if ((c < 0x20) && (PG(syslog_filter) == PHP_SYSLOG_FILTER_ALL)) {
+			smart_string_appendc(&sbuf, c);
+		} else {
+			const char xdigits[] = "0123456789abcdef";
+
+			smart_string_appendl(&sbuf, "\\x", 2);
+			smart_string_appendc(&sbuf, xdigits[c >> 4]);
+			smart_string_appendc(&sbuf, xdigits[c & 0xf]);
+		}
+	}
+
+	/* Smart string is not NUL terminated */
+	syslog(priority, "%.*s", (int)sbuf.len, sbuf.c);
+	smart_string_free(&sbuf);
+}
+
 #ifdef PHP_WIN32
 PHPAPI void php_syslog(int priority, const char *format, ...) /* {{{ */
 {
@@ -54,10 +93,7 @@ PHPAPI void php_syslog(int priority, const char *format, ...) /* {{{ */
 #else
 PHPAPI void php_syslog(int priority, const char *format, ...) /* {{{ */
 {
-	const char *ptr;
-	unsigned char c;
-	smart_string fbuf = {0};
-	smart_string sbuf = {0};
+	zend_string *fbuf = NULL;
 	va_list args;
 
 	/*
@@ -70,46 +106,12 @@ PHPAPI void php_syslog(int priority, const char *format, ...) /* {{{ */
 	}
 
 	va_start(args, format);
-	zend_printf_to_smart_string(&fbuf, format, args);
-	smart_string_0(&fbuf);
+	fbuf = zend_vstrpprintf(0, format, args);
 	va_end(args);
 
-	if (PG(syslog_filter) == PHP_SYSLOG_FILTER_RAW) {
-		/* Just send it directly to the syslog */
-		syslog(priority, "%.*s", (int)fbuf.len, fbuf.c);
-		smart_string_free(&fbuf);
-		return;
-	}
+	php_syslog_str(priority, fbuf);
 
-	for (ptr = fbuf.c; ; ++ptr) {
-		c = *ptr;
-		if (c == '\0') {
-			syslog(priority, "%.*s", (int)sbuf.len, sbuf.c);
-			break;
-		}
-
-		/* check for NVT ASCII only unless test disabled */
-		if (((0x20 <= c) && (c <= 0x7e)))
-			smart_string_appendc(&sbuf, c);
-		else if ((c >= 0x80) && (PG(syslog_filter) != PHP_SYSLOG_FILTER_ASCII))
-			smart_string_appendc(&sbuf, c);
-		else if (c == '\n') {
-			syslog(priority, "%.*s", (int)sbuf.len, sbuf.c);
-			smart_string_reset(&sbuf);
-		} else if ((c < 0x20) && (PG(syslog_filter) == PHP_SYSLOG_FILTER_ALL))
-			smart_string_appendc(&sbuf, c);
-		else {
-			const char xdigits[] = "0123456789abcdef";
-
-			smart_string_appendl(&sbuf, "\\x", 2);
-			smart_string_appendc(&sbuf, xdigits[(c / 0x10)]);
-			c &= 0x0f;
-			smart_string_appendc(&sbuf, xdigits[c]);
-		}
-	}
-
-	smart_string_free(&fbuf);
-	smart_string_free(&sbuf);
+	zend_string_release(fbuf);
 }
 /* }}} */
 #endif
diff --git a/main/php_syslog.h b/main/php_syslog.h
index ded7299d8f0..2005a03ef9e 100644
--- a/main/php_syslog.h
+++ b/main/php_syslog.h
@@ -35,6 +35,7 @@
 #define PHP_SYSLOG_FILTER_RAW		3
 
 BEGIN_EXTERN_C()
+PHPAPI void php_syslog_str(int priority, const zend_string* message);
 PHPAPI void php_syslog(int, const char *format, ...);
 PHPAPI void php_openlog(const char *, int, int);
 END_EXTERN_C()