diff --git a/src/cmd/go/internal/modload/query.go b/src/cmd/go/internal/modload/query.go
index 53278b91002..031e45938a5 100644
--- a/src/cmd/go/internal/modload/query.go
+++ b/src/cmd/go/internal/modload/query.go
@@ -79,7 +79,7 @@ func queryProxy(proxy, path, query, current string, allowed func(module.Version)
 	if current != "" && !semver.IsValid(current) {
 		return nil, fmt.Errorf("invalid previous version %q", current)
 	}
-	if cfg.BuildMod != "" && cfg.BuildMod != "mod" {
+	if cfg.BuildMod == "vendor" {
 		return nil, errQueryDisabled
 	}
 	if allowed == nil {
diff --git a/src/cmd/go/testdata/script/mod_readonly.txt b/src/cmd/go/testdata/script/mod_readonly.txt
index 1d1771e9cc0..77fc735d572 100644
--- a/src/cmd/go/testdata/script/mod_readonly.txt
+++ b/src/cmd/go/testdata/script/mod_readonly.txt
@@ -34,6 +34,11 @@ go list all
 go clean -modcache
 go list all
 
+# -mod=readonly must not cause 'go list -m' to fail.
+# (golang.org/issue/36478)
+go list -m all
+! stderr 'cannot query module'
+
 # -mod=readonly should reject inconsistent go.mod files
 # (ones that would be rewritten).
 go mod edit -require rsc.io/sampler@v1.2.0