diff --git a/projects/unbound.net/package.yml b/projects/unbound.net/package.yml
index e5c7b920..7e16bbf4 100644
--- a/projects/unbound.net/package.yml
+++ b/projects/unbound.net/package.yml
@@ -14,6 +14,7 @@ build:
     tea.xyz/gx/cc: c99
     tea.xyz/gx/make: '*'
     libexpat.github.io: '*'
+    github.com/westes/flex: '*'
   script: |
     ./configure $ARGS
     make -j {{ hw.concurrency }} install
@@ -43,4 +44,4 @@ provides:
   - bin/unbound-checkconf
   - bin/unbound-control
   - bin/unbound-control-setup
-  - bin/unbound-host
\ No newline at end of file
+  - bin/unbound-host