diff --git a/Dockerfile b/Dockerfile
index f82343c..e712668 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,7 +1,7 @@
 # GC-Forge runner image — embeds the workload harness on Temurin 21.
 # Used by `make demo` (iter 1) and by the DockerRunner backend (iter 3).
 
-FROM eclipse-temurin:21-jdk-jammy
+FROM eclipse-temurin:25-jdk-jammy
 
 LABEL org.opencontainers.image.title="gc-forge-runner"
 LABEL org.opencontainers.image.description="GC-Forge workload harness on Eclipse Temurin 21."
diff --git a/Dockerfile.jdk17 b/Dockerfile.jdk17
index e407327..e2fc955 100644
--- a/Dockerfile.jdk17
+++ b/Dockerfile.jdk17
@@ -2,7 +2,7 @@
 # Sibling of Dockerfile (which targets Temurin 21). Used to produce the
 # JDK-17 half of the GC-Insight learning corpus.
 
-FROM eclipse-temurin:17-jdk-jammy
+FROM eclipse-temurin:25-jdk-jammy
 
 LABEL org.opencontainers.image.title="gc-forge-runner"
 LABEL org.opencontainers.image.description="GC-Forge workload harness on Eclipse Temurin 17."