Add CHANGES and release notes for [GL #4124]

CHANGES

@@ -1,3 +1,6 @@
+6224.	[bug]		Check the If-Modified-Since value length to prevent
+			out-of-bounds write. [GL #4124]
+
 6223.	[func]		Make -E engine option for OpenSSL Engine API use only.
 			OpenSSL Provider API will now require engine to not be
 			set. [GL #8153]

doc/notes/notes-current.rst

@@ -37,6 +37,14 @@ Bug Fixes
 
 - None.
 
+- The value of If-Modified-Since header in statistics channel was not checked
+  for length leading to possible buffer overflow by an authorized user.  We
+  would like to emphasize that statistics channel must be properly setup to
+  allow access only from authorized users of the system. :gl:`#4124`
+
+  This was reported independently by Eric Sesterhenn of X41 D-SEC and Cameron
+  Whitehead.
+
 Known Issues
 ~~~~~~~~~~~~