diff --git a/infra/docker/Dockerfile.ci-builder b/infra/docker/Dockerfile.ci-builder
index 80c9de5a9..1afaf60c8 100644
--- a/infra/docker/Dockerfile.ci-builder
+++ b/infra/docker/Dockerfile.ci-builder
@@ -1,11 +1,14 @@
 # Pre-baked CI builder image for Foxhunt
-# Contains: CUDA 12.9, Rust 1.89, protoc, sccache, git, OpenSSL, lld, make
+# Contains: CUDA 13.0, Rust 1.89, protoc, sccache, git, OpenSSL, lld, make
 # No cuDNN — zero conv ops in codebase, all cudnn feature flags removed
 # Build: docker build -f infra/docker/Dockerfile.ci-builder -t foxhunt-ci-builder .
 # Push:  docker tag foxhunt-ci-builder git.fxhnt.ai:5050/root/foxhunt/ci-builder:latest
 #        docker push git.fxhnt.ai:5050/root/foxhunt/ci-builder:latest
+#
+# CUDA version MUST match the H100 runtime (GPU operator installs Driver 580 → CUDA 13.0).
+# Mismatch causes cublasLtMatmul CUBLAS_STATUS_NOT_SUPPORTED at runtime.
 
-FROM nvidia/cuda:12.9.1-devel-ubuntu24.04
+FROM nvidia/cuda:13.0.0-devel-ubuntu24.04
 
 ENV DEBIAN_FRONTEND=noninteractive