diff --git a/hack/update-manifests.sh b/hack/update-manifests.sh
index 44cff36120..0814c13732 100755
--- a/hack/update-manifests.sh
+++ b/hack/update-manifests.sh
@@ -18,6 +18,10 @@ IMAGE_TAG="${IMAGE_TAG:-}"
 # if the tag has not been declared, and we are on a release branch, use the VERSION file.
 if [ "$IMAGE_TAG" = "" ]; then
   branch=$(git rev-parse --abbrev-ref HEAD)
+  # In GitHub Actions PRs, HEAD is detached; use GITHUB_BASE_REF (the target branch) instead
+  if [ "$branch" = "HEAD" ] && [ -n "${GITHUB_BASE_REF:-}" ]; then
+    branch="$GITHUB_BASE_REF"
+  fi
   if [[ $branch = release-* ]]; then
     pwd
     IMAGE_TAG=v$(cat $SRCROOT/VERSION)