From 7a15ba7284b07d87bd9901e933552cd3802bb30f Mon Sep 17 00:00:00 2001
From: William Bader <william@newspapersystems.com>
Date: Mon, 21 Apr 2025 19:47:55 +0200
Subject: [PATCH] Fix NULL dereference in active_edges_to_traps() provoked by
 https://gitlab.freedesktop.org/poppler/poppler/-/issues/1579

---
 src/cairo-bentley-ottmann-rectangular.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/cairo-bentley-ottmann-rectangular.c b/src/cairo-bentley-ottmann-rectangular.c
index 65f95d797..5bca289cd 100644
--- a/src/cairo-bentley-ottmann-rectangular.c
+++ b/src/cairo-bentley-ottmann-rectangular.c
@@ -468,6 +468,9 @@ active_edges_to_traps (sweep_line_t *sweep)
 	    edge_t *left, *right;
 	    int winding;
 
+	    if (unlikely (pos == NULL))
+		break;
+
 	    left = pos;
 	    winding = left->dir;
 
@@ -503,6 +506,8 @@ active_edges_to_traps (sweep_line_t *sweep)
 		 * boxes.
 		 */
 		winding += right->dir;
+		if (unlikely (right->next == NULL))
+	            break;
 		if (winding == 0 && right->x != right->next->x)
 		    break;