diff --git a/toolchain/local/triplet/os.bzl b/toolchain/local/triplet/os.bzl
index a7de60651c590298dc7089ecd47a48afde8c74de..b2a9afcb70bd78209cb10d20b3d1f8a3c790502f 100644
--- a/toolchain/local/triplet/os.bzl
+++ b/toolchain/local/triplet/os.bzl
@@ -118,6 +118,7 @@ def _uname(rctx, path):
 
     major, minor, patch = split(version, ".", {
         3: lambda x, y, z: (x, y, z),
+        4: lambda x, y, z, _: (x, y, z),
     })
 
     if rctx.path("/.dockerenv").exists: