diff --git a/Dockerfile b/Dockerfile
index a8bea85..54f9cd5 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -19,6 +19,9 @@ RUN apt-get update && apt-get install -y \
     meson ninja-build \
     && rm -rf /var/lib/apt/lists/*
 
+# Provide optional vendor tarballs (e.g., GNUnet) to the build
+COPY vendor/ /vendor/
+
 # GNUnet (falls nicht schon systemweit neu genug)
 RUN set -e; \
     mkdir -p /src && cd /src; \