diff --git a/light/ltface.cc b/light/ltface.cc
index 7e09ca08..d6ec5a47 100644
--- a/light/ltface.cc
+++ b/light/ltface.cc
@@ -2760,6 +2760,10 @@ LightFace(const bsp2_t *bsp, bsp2_dface_t *face, facesup_t *facesup, const globa
     if (!Q_strcasecmp(texname, "skip"))
         return;
     
+    /* don't bother with degenerate faces */
+    if (face->numedges < 3)
+        return;
+    
     /* all good, this face is going to be lightmapped. */
     lightsurf_t *lightsurf = new lightsurf_t {};
     lightsurf->cfg = &cfg;
diff --git a/light/phong.cc b/light/phong.cc
index c29e3e43..7ba98e47 100644
--- a/light/phong.cc
+++ b/light/phong.cc
@@ -150,8 +150,13 @@ const qvec3f GetSurfaceVertexNormal(const bsp2_t *bsp, const bsp2_dface_t *f, co
 {
     Q_assert(s_builtPhongCaches);
     
-    const auto &face_normals_vector = vertex_normals.at(f);
-    return face_normals_vector.at(vertindex);
+    // handle degenerate faces
+    const auto it = vertex_normals.find(f);
+    if (it == vertex_normals.end()) {
+        return qvec3f(0,0,0);
+    }
+    const auto &face_normals_vec = it->second;
+    return face_normals_vec.at(vertindex);
 }
 
 static bool