diff --git a/src/libstore/path.cc b/src/libstore/path.cc
index c896ff927..2f929b7b3 100644
--- a/src/libstore/path.cc
+++ b/src/libstore/path.cc
@@ -64,6 +64,11 @@ StorePath Store::parseStorePath(std::string_view path) const
 
 std::optional<StorePath> Store::maybeParseStorePath(std::string_view path) const
 {
+    // If it's not an absolute path, or if the dirname of the path isn't /nix/store
+    // (or whatever our storeDir is), then it can't be a store path.
+    if ((path.size() > 0 && path[0] != '/') || dirOf(canonPath(path)) != this->storeDir) {
+        return std::nullopt;
+    }
     try {
         return parseStorePath(path);
     } catch (Error &) {