Upstream:
3705f82b6483c7906cf08cd6b9dcdcd59c61d779
Index: tiff-4.6.0/libtiff/tif_dirinfo.c
===================================================================
--- tiff-4.6.0.orig/libtiff/tif_dirinfo.c
+++ tiff-4.6.0/libtiff/tif_dirinfo.c
@@ -887,7 +887,7 @@ const TIFFField *_TIFFFindOrRegisterFiel
     if (fld == NULL)
     {
         fld = _TIFFCreateAnonField(tif, tag, dt);
-        if (!_TIFFMergeFields(tif, fld, 1))
+        if (fld == NULL || !_TIFFMergeFields(tif, fld, 1))
             return NULL;
     }
 
Index: tiff-4.6.0/libtiff/tif_dirread.c
===================================================================
--- tiff-4.6.0.orig/libtiff/tif_dirread.c
+++ tiff-4.6.0/libtiff/tif_dirread.c
@@ -4260,11 +4260,9 @@ int TIFFReadDirectory(TIFF *tif)
                                 dp->tdir_tag, dp->tdir_tag);
                 /* the following knowingly leaks the
                    anonymous field structure */
-                if (!_TIFFMergeFields(
-                        tif,
-                        _TIFFCreateAnonField(tif, dp->tdir_tag,
-                                             (TIFFDataType)dp->tdir_type),
-                        1))
+				const TIFFField *fld = _TIFFCreateAnonField(
+                    tif, dp->tdir_tag, (TIFFDataType)dp->tdir_type);
+                if (fld == NULL || !_TIFFMergeFields(tif, fld, 1))
                 {
                     TIFFWarningExtR(
                         tif, module,
@@ -5138,11 +5136,9 @@ int TIFFReadCustomDirectory(TIFF *tif, t
                             "Unknown field with tag %" PRIu16 " (0x%" PRIx16
                             ") encountered",
                             dp->tdir_tag, dp->tdir_tag);
-            if (!_TIFFMergeFields(
-                    tif,
-                    _TIFFCreateAnonField(tif, dp->tdir_tag,
-                                         (TIFFDataType)dp->tdir_type),
-                    1))
+			const TIFFField *fld = _TIFFCreateAnonField(
+                tif, dp->tdir_tag, (TIFFDataType)dp->tdir_type);
+            if (fld == NULL || !_TIFFMergeFields(tif, fld, 1))
             {
                 TIFFWarningExtR(tif, module,
                                 "Registering anonymous field with tag %" PRIu16