diff --git a/build/pkgs/configure/checksums.ini b/build/pkgs/configure/checksums.ini
index 3ab3b15c533..72754d1d382 100644
--- a/build/pkgs/configure/checksums.ini
+++ b/build/pkgs/configure/checksums.ini
@@ -1,3 +1,3 @@
 tarball=configure-VERSION.tar.gz
-sha1=8164bb387998beb2257d3e09f10697195e958860
-sha256=981eb6316a4ff9179b0eb7242e23f4cb39e00372d2aa855efde6885e599e26e8
+sha1=ee7627e65e85f8f74e5bdff5201f6de13106050e
+sha256=8c6746170ea46928047268bc0f8bbc378ed1af8c62fb5e51b575e0a7bbf4dbea
diff --git a/build/pkgs/configure/package-version.txt b/build/pkgs/configure/package-version.txt
index 7da33645e59..c0d8ac28e41 100644
--- a/build/pkgs/configure/package-version.txt
+++ b/build/pkgs/configure/package-version.txt
@@ -1 +1 @@
-fb2b8c823bcc3f168c1e6e467f254557fa714db9
+b72c3bed388e4e57ff7fca3151a57fda13eff35a
diff --git a/src/sage/combinat/root_system/cartan_matrix.py b/src/sage/combinat/root_system/cartan_matrix.py
index 383f61f25e9..1f25c8c554d 100644
--- a/src/sage/combinat/root_system/cartan_matrix.py
+++ b/src/sage/combinat/root_system/cartan_matrix.py
@@ -388,6 +388,14 @@ def _CM_init(self, cartan_type, index_set, cartan_type_check):
 
             sage: C = CartanMatrix(['A',1,1])  # indirect doctest                       # needs sage.graphs
             sage: TestSuite(C).run(skip=["_test_category", "_test_change_ring"])        # needs sage.graphs
+
+        Check that :issue:`37979` is fixed::
+
+            sage: C = CartanMatrix([[2]], index_set=(4,))
+            sage: C.index_set()
+            (4,)
+            sage: CartanType("A3").subtype((2,)) is CartanType("A1").relabel({1:2})
+            True
         """
         self._index_set = index_set
         self.set_immutable()
@@ -396,6 +404,8 @@ def _CM_init(self, cartan_type, index_set, cartan_type_check):
             cartan_type = CartanType(cartan_type)
         elif self.nrows() == 1:
             cartan_type = CartanType(['A', 1])
+            if index_set != (1,):
+                cartan_type = cartan_type.relabel({1: index_set[0]})
         elif cartan_type_check:
             # Placeholder so we don't have to reimplement creating a
             #   Dynkin diagram from a Cartan matrix