diff -Nru cups-2.3.1/debian/changelog cups-2.3.1/debian/changelog
--- cups-2.3.1/debian/changelog	2023-09-11 16:30:19.000000000 +0000
+++ cups-2.3.1/debian/changelog	2023-09-15 11:20:26.000000000 +0000
@@ -1,3 +1,12 @@
+cups (2.3.1-9ubuntu1.6) focal-security; urgency=medium
+
+  * SECURITY UPDATE: Postscript parsing heap overflow
+    - debian/patches/CVE-2023-4504.patch: properly check for end of buffer
+      in cups/raster-interpret.c.
+    - CVE-2023-4504
+
+ -- Marc Deslauriers <marc.deslauriers@ubuntu.com>  Fri, 15 Sep 2023 07:20:26 -0400
+
 cups (2.3.1-9ubuntu1.5) focal-security; urgency=medium
 
   * SECURITY UPDATE: recently printed documents authentication issue
diff -Nru cups-2.3.1/debian/patches/CVE-2023-4504.patch cups-2.3.1/debian/patches/CVE-2023-4504.patch
--- cups-2.3.1/debian/patches/CVE-2023-4504.patch	1970-01-01 00:00:00.000000000 +0000
+++ cups-2.3.1/debian/patches/CVE-2023-4504.patch	2023-09-15 11:20:20.000000000 +0000
@@ -0,0 +1,36 @@
+From a9a7daa77699bd58001c25df8a61a8029a217ddf Mon Sep 17 00:00:00 2001
+From: Zdenek Dohnal <zdohnal@redhat.com>
+Date: Fri, 1 Sep 2023 16:47:29 +0200
+Subject: [PATCH] raster-interpret.c: Fix CVE-2023-4504
+
+We didn't check for end of buffer if it looks there is an escaped
+character - check for NULL terminator there and if found, return NULL
+as return value and in `ptr`, because a lone backslash is not
+a valid PostScript character.
+---
+ cups/raster-interpret.c | 14 +++++++++++++-
+ 1 file changed, 13 insertions(+), 1 deletion(-)
+
+--- a/cups/raster-interpret.c
++++ b/cups/raster-interpret.c
+@@ -1113,7 +1113,19 @@ scan_ps(_cups_ps_stack_t *st,		/* I  - S
+ 
+ 	    cur ++;
+ 
+-            if (*cur == 'b')
++	   /*
++	    * Return NULL if we reached NULL terminator, a lone backslash
++            * is not a valid character in PostScript.
++	    */
++
++	    if (!*cur)
++	    {
++	      *ptr = NULL;
++
++	      return (NULL);
++	    }
++
++	    if (*cur == 'b')
+ 	      *valptr++ = '\b';
+ 	    else if (*cur == 'f')
+ 	      *valptr++ = '\f';
diff -Nru cups-2.3.1/debian/patches/series cups-2.3.1/debian/patches/series
--- cups-2.3.1/debian/patches/series	2023-09-11 16:30:10.000000000 +0000
+++ cups-2.3.1/debian/patches/series	2023-09-15 11:20:20.000000000 +0000
@@ -43,3 +43,4 @@
 CVE-2023-32324.patch
 CVE-2023-34241.patch
 CVE-2023-32360.patch
+CVE-2023-4504.patch