diff -u xorg-server-21.1.3/debian/changelog xorg-server-21.1.3/debian/changelog
--- xorg-server-21.1.3/debian/changelog
+++ xorg-server-21.1.3/debian/changelog
@@ -1,3 +1,12 @@
+xorg-server (2:21.1.3-2ubuntu2.9) jammy-security; urgency=medium
+
+  * SECURITY UPDATE: Overlay Window Use-After-Free
+    - debian/patches/CVE-2023-1393.patch: fix use-after-free of the COW in
+      composite/compwindow.c.
+    - CVE-2023-1393
+
+ -- Marc Deslauriers <marc.deslauriers@ubuntu.com>  Wed, 29 Mar 2023 08:52:16 -0400
+
 xorg-server (2:21.1.3-2ubuntu2.8) jammy; urgency=medium
 
   * patches: Force update LEDs after device state update. (LP: #1993621)
diff -u xorg-server-21.1.3/debian/patches/series xorg-server-21.1.3/debian/patches/series
--- xorg-server-21.1.3/debian/patches/series
+++ xorg-server-21.1.3/debian/patches/series
@@ -43,0 +44 @@
+CVE-2023-1393.patch
only in patch2:
unchanged:
--- xorg-server-21.1.3.orig/debian/patches/CVE-2023-1393.patch
+++ xorg-server-21.1.3/debian/patches/CVE-2023-1393.patch
@@ -0,0 +1,42 @@
+From 26ef545b3502f61ca722a7a3373507e88ef64110 Mon Sep 17 00:00:00 2001
+From: Olivier Fourdan <ofourdan@redhat.com>
+Date: Mon, 13 Mar 2023 11:08:47 +0100
+Subject: [PATCH] composite: Fix use-after-free of the COW
+
+ZDI-CAN-19866/CVE-2023-1393
+
+If a client explicitly destroys the compositor overlay window (aka COW),
+we would leave a dangling pointer to that window in the CompScreen
+structure, which will trigger a use-after-free later.
+
+Make sure to clear the CompScreen pointer to the COW when the latter gets
+destroyed explicitly by the client.
+
+This vulnerability was discovered by:
+Jan-Niklas Sohn working with Trend Micro Zero Day Initiative
+
+Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
+Reviewed-by: Adam Jackson <ajax@redhat.com>
+---
+ composite/compwindow.c | 5 +++++
+ 1 file changed, 5 insertions(+)
+
+diff --git a/composite/compwindow.c b/composite/compwindow.c
+index 4e2494b86b..b30da589e9 100644
+--- a/composite/compwindow.c
++++ b/composite/compwindow.c
+@@ -620,6 +620,11 @@ compDestroyWindow(WindowPtr pWin)
+     ret = (*pScreen->DestroyWindow) (pWin);
+     cs->DestroyWindow = pScreen->DestroyWindow;
+     pScreen->DestroyWindow = compDestroyWindow;
++
++    /* Did we just destroy the overlay window? */
++    if (pWin == cs->pOverlayWin)
++        cs->pOverlayWin = NULL;
++
+ /*    compCheckTree (pWin->drawable.pScreen); can't check -- tree isn't good*/
+     return ret;
+ }
+-- 
+GitLab
+