diff --git a/uv.spec b/uv.spec
index fa5b3af..fdeeaa7 100644
--- a/uv.spec
+++ b/uv.spec
@@ -746,6 +746,19 @@ skip="${skip-} --skip tests::built_by_uv_building"
 # https://github.com/astral-sh/uv/pull/14243#issuecomment-3001792931.
 skip="${skip-} --skip registry_client::tests::test_redirect_preserve_fragment"
 
+%ifarch s390x
+# ---- registry_client::tests::test_redirect_to_server_with_credentials stdout ----
+# thread 'registry_client::tests::test_redirect_to_server_with_credentials'
+# panicked at crates/uv-client/src/registry_client.rs:1292:9:
+# assertion `left == right` failed: Requests should fail if credentials are missing
+#   left: 200
+#  right: 401
+# Ideally, we would report this upstream, but "cargo test -p uv-client --lib"
+# does not fail in a git checkout in an emulated s390x chroot, so it’s
+# difficult to do so usefully. More information is needed.
+skip="${skip-} --skip registry_client::tests::test_redirect_to_server_with_credentials"
+%endif
+
 %cargo_test -- -- --exact ${skip-}
 %endif