diff --git a/NEWS b/NEWS
index 5f048e0f89a..5e940ee0217 100644
--- a/NEWS
+++ b/NEWS
@@ -61,6 +61,9 @@ PHP                                                                        NEWS
   . Fixed bug #60994 (Reading a multibyte CLOB caps at 8192 chars).
     (Michael Voříšek)
 
+- PHPDBG:
+  . Fixed bug GH-10715 (heap buffer overflow on --run option misuse). (nielsdos)
+
 - PGSQL:
   . Fix GH-10672 (pg_lo_open segfaults in the strict_types mode). (girgias)
 
diff --git a/sapi/phpdbg/phpdbg_out.c b/sapi/phpdbg/phpdbg_out.c
index a6eb84de2c1..af2f3b98d2b 100644
--- a/sapi/phpdbg/phpdbg_out.c
+++ b/sapi/phpdbg/phpdbg_out.c
@@ -143,7 +143,11 @@ PHPDBG_API int phpdbg_vprint(int type, int fd, const char *strfmt, va_list args)
 		return msglen;
 	}
 
-	len = phpdbg_process_print(fd, type, msg, msglen);
+	if (UNEXPECTED(msglen == 0)) {
+		len = 0;
+	} else {
+		len = phpdbg_process_print(fd, type, msg, msglen);
+	}
 
 	if (msg) {
 		free(msg);
diff --git a/sapi/phpdbg/tests/gh10715.phpt b/sapi/phpdbg/tests/gh10715.phpt
new file mode 100644
index 00000000000..13edd9afdd8
Binary files /dev/null and b/sapi/phpdbg/tests/gh10715.phpt differ