diff --git a/NEWS b/NEWS
index eb4238ab78c..08da27c53e6 100644
--- a/NEWS
+++ b/NEWS
@@ -21,6 +21,9 @@ PHP                                                                        NEWS
   . Fixed bug #63590 (Different results in TS and NTS under Windows).
     (Anatoliy)
 
+- FPM:
+  . Fixed bug #63581 Possible null dereference and buffer overflow (Remi)
+
 - Imap:
   . Fixed Bug #63126 DISABLE_AUTHENTICATOR ignores array (Remi)
 
diff --git a/sapi/fpm/fpm/fpm_log.c b/sapi/fpm/fpm/fpm_log.c
index 69bd31b1135..6b014b5005a 100644
--- a/sapi/fpm/fpm/fpm_log.c
+++ b/sapi/fpm/fpm/fpm_log.c
@@ -96,7 +96,7 @@ int fpm_log_init_child(struct fpm_worker_pool_s *wp)  /* {{{ */
 int fpm_log_write(char *log_format TSRMLS_DC) /* {{{ */
 {
 	char *s, *b;
-	char buffer[FPM_LOG_BUFFER];
+	char buffer[FPM_LOG_BUFFER+1];
 	int token, test;
 	size_t len, len2;
 	struct fpm_scoreboard_proc_s proc, *proc_p;
@@ -146,9 +146,10 @@ int fpm_log_write(char *log_format TSRMLS_DC) /* {{{ */
 	s = log_format;
 
 	while (*s != '\0') {
-		if (len > FPM_LOG_BUFFER) {
+		/* Test is we have place for 1 more char. */
+		if (len >= FPM_LOG_BUFFER) {
 			zlog(ZLOG_NOTICE, "the log buffer is full (%d). The access log request has been truncated.", FPM_LOG_BUFFER);
-			len = FPM_LOG_BUFFER - 1;
+			len = FPM_LOG_BUFFER;
 			break;
 		}