doc: vulnerabilities: Add information about new vulnerabilities

Add a placeholder for CVE-2023-1901 and CVE-2023-1902.

Signed-off-by: Flavio Ceolin <[email protected]>

Author: Flavio Ceolin

doc/security/vulnerabilities.rst

@@ -1312,3 +1312,13 @@ This has been fixed in main for v3.3.0
 
 - `PR 54381 fix for v2.7.4
   <https://github.com/zephyrproject-rtos/zephyr/pull/54381>`_
+
+CVE-2023-1901
+-------------
+
+Under embargo until 2023/07/04
+
+CVE-2023-1902
+-------------
+
+Under embargo until 2023/07/04