There is an assertion in function _cairo_arc_in_direction().

CVE: CVE-2019-6461
Upstream-Status: Pending
Signed-off-by: Ross Burton <ross.burton@intel.com>

diff --git a/src/cairo-arc.c b/src/cairo-arc.c
index 390397bae..1bde774a4 100644
--- a/src/cairo-arc.c
+++ b/src/cairo-arc.c
@@ -186,7 +186,8 @@ _cairo_arc_in_direction (cairo_t	  *cr,
     if (cairo_status (cr))
         return;
 
-    assert (angle_max >= angle_min);
+    if (angle_max < angle_min)
+       return;
 
     if (angle_max - angle_min > 2 * M_PI * MAX_FULL_CIRCLES) {
 	angle_max = fmod (angle_max - angle_min, 2 * M_PI);