diff --git a/Dockerfile.ubuntu b/Dockerfile.ubuntu
index fbfbc42..83f617b 100644
--- a/Dockerfile.ubuntu
+++ b/Dockerfile.ubuntu
@@ -19,7 +19,7 @@ SHELL ["/bin/bash", "-o", "pipefail", "-c"]
 RUN apt-get update \
   && apt-get -y install --no-install-recommends --no-install-suggests \
   ## common permanent packages
-  "ca-certificates=20260601~26.04.1" \
+  "ca-certificates=20260816ubuntu0.26.04.1" \
   ## add ephemeral packages
   "curl=8.18.0-1ubuntu2.8" \
   "gpg=2.4.8-4ubuntu3.1" \