diff --git a/pkgs/applications/networking/browsers/firefox/packages.nix b/pkgs/applications/networking/browsers/firefox/packages.nix
index 61cc6e936d2e..54be5fd32b6e 100644
--- a/pkgs/applications/networking/browsers/firefox/packages.nix
+++ b/pkgs/applications/networking/browsers/firefox/packages.nix
@@ -175,6 +175,7 @@ in {
       ./no-buildconfig.patch
       missing-documentation-patch
     ];
+    meta.knownVulnerabilities = [ "Support ended around October 2019." ];
   };
 
   # Similarly to firefox-esr-52 above.