diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -146,6 +146,11 @@
 Windows Support
 ---------------
 
+- Windows on Arm64: programs using the C standard library's setjmp and longjmp
+  functions may crash with a "Security check failure or stack buffer overrun"
+  exception. To workaround (with reduced security), compile with
+  /guard:cf,nolongjmp.
+
 C Language Changes in Clang
 ---------------------------