diff --git a/electrum/plugins/coldcard/README.md b/electrum/plugins/coldcard/README.md
index c5cf55bc1f9..139aaead1c4 100644
--- a/electrum/plugins/coldcard/README.md
+++ b/electrum/plugins/coldcard/README.md
@@ -1,5 +1,9 @@
 # Coldcard Hardware Wallet Plugin
 
+## Security notice
+
+Coinkite disclosed (July 2026) a firmware build error that reduced generated-seed entropy on **Coldcard Mk3** (firmware 4.0.1-5.0.3) and pre-fix **Mk4/Q**. Seeds generated on-device without extra dice rolls may be brute-forceable. Update to fixed firmware, generate a new seed and move your funds. See the [Coinkite advisory](https://blog.coinkite.com/coldcard-mk3-seed-generation-warning/).
+
 ## Just the glue please
 
 This code connects the public USB API and Electrum. Leverages all