diff --git a/src/cmd/go/internal/modload/init.go b/src/cmd/go/internal/modload/init.go
index 89eeb5c71a..4ba1bf98ee 100644
--- a/src/cmd/go/internal/modload/init.go
+++ b/src/cmd/go/internal/modload/init.go
@@ -1472,13 +1472,12 @@ func setDefaultBuildMod() {
 			vendorDir = filepath.Join(modRoots[0], "vendor")
 		}
 		if fi, err := fsys.Stat(vendorDir); err == nil && fi.IsDir() {
-			modGo := "unspecified"
 			if goVersion != "" {
 				if gover.Compare(goVersion, "1.14") < 0 {
 					// The go version is less than 1.14. Don't set -mod=vendor by default.
 					// Since a vendor directory exists, we should record why we didn't use it.
 					// This message won't normally be shown, but it may appear with import errors.
-					cfg.BuildModReason = fmt.Sprintf("Go version in "+versionSource+" is %s, so vendor directory was not used.", modGo)
+					cfg.BuildModReason = fmt.Sprintf("Go version in "+versionSource+" is %s, so vendor directory was not used.", goVersion)
 				} else {
 					vendoredWorkspace, err := modulesTextIsForWorkspace(vendorDir)
 					if err != nil {
@@ -1499,9 +1498,9 @@ func setDefaultBuildMod() {
 						return
 					}
 				}
-				modGo = goVersion
+			} else {
+				cfg.BuildModReason = fmt.Sprintf("Go version in " + versionSource + " is unspecified, so vendor directory was not used.")
 			}
-
 		}
 	}
 
diff --git a/src/cmd/go/testdata/script/list_buildmod_reason_issue67587.txt b/src/cmd/go/testdata/script/list_buildmod_reason_issue67587.txt
new file mode 100644
index 0000000000..a89f0e4f9d
--- /dev/null
+++ b/src/cmd/go/testdata/script/list_buildmod_reason_issue67587.txt
@@ -0,0 +1,26 @@
+cd thirteen
+! go list -deps
+stderr 	'(Go version in go.mod is 1.13, so vendor directory was not used.)'
+
+cd ../unspecified
+! go list -deps
+stderr 	'(Go version in go.mod is unspecified, so vendor directory was not used.)'
+
+-- thirteen/foo.go --
+package foo
+
+import _ "github.com/foo/bar"
+-- thirteen/go.mod --
+module example.com
+
+go 1.13
+-- thirteen/vendor/github.com/foo/bar/bar.go --
+package bar
+-- unspecified/foo.go --
+package foo
+
+import _ "github.com/foo/bar"
+-- unspecified/go.mod --
+module example.com
+-- unspecified/vendor/github.com/foo/bar/bar.go --
+package bar
\ No newline at end of file