diff --git a/scripts/cli/commands/artifact/cli_artifact_apply.sh b/scripts/cli/commands/artifact/cli_artifact_apply.sh
index c1fc19d..1adde75 100644
--- a/scripts/cli/commands/artifact/cli_artifact_apply.sh
+++ b/scripts/cli/commands/artifact/cli_artifact_apply.sh
@@ -75,7 +75,7 @@ _artifactRmFile() {
 # ----------------------------------------------------------------------------
 _artifactResolve() {
     local id="$1"
-    _ART_INDEX="$(lpFetchIndex)" || { isError "artifact: could not fetch/verify the index."; return 1; }
+    lpFetchIndexInto _ART_INDEX || { isError "artifact: could not fetch/verify the index."; return 1; }
 
     local art; art="$(printf '%s' "$_ART_INDEX" | jq -ce --arg id "$id" '.artifacts[]? | select(.id==$id)' 2>/dev/null)"
     [[ -n "$art" ]] || { isError "artifact: id '$id' not found in the signed index."; return 1; }
@@ -534,7 +534,7 @@ artifactApplyAuto() {
     local policy="${CFG_HOTFIX_AUTO:-security-breakage}"
     [[ "$policy" == "off" ]] && { isNotice "Hotfix auto-apply is off (CFG_HOTFIX_AUTO=off)."; return 0; }
 
-    local index; index="$(lpFetchIndex)" || { isNotice "artifact apply-auto: no index available."; return 0; }
+    local index; lpFetchIndexInto index || { isNotice "artifact apply-auto: no index available."; return 0; }
     if [[ "$LP_INDEX_SIGSTATE" != "verified" ]]; then
         isNotice "artifact apply-auto: index is unsigned (signing not activated) — not auto-applying."; return 0
     fi
diff --git a/scripts/cli/commands/artifact/cli_artifact_commands.sh b/scripts/cli/commands/artifact/cli_artifact_commands.sh
index 8a23873..40dd035 100644
--- a/scripts/cli/commands/artifact/cli_artifact_commands.sh
+++ b/scripts/cli/commands/artifact/cli_artifact_commands.sh
@@ -97,7 +97,7 @@ artifactListIndex()
     isHeader "Artifact index ($(lpReleaseChannel))"
 
     local json
-    if ! json="$(lpFetchIndex)"; then
+    if ! lpFetchIndexInto json; then
         isError "Could not fetch or verify the artifact index from $(lpArtifactIndexUrl)."
         isNotice "Nothing is published yet, or the channel is unreachable. (This is expected before the first index ships.)"
         return 1
diff --git a/scripts/source/artifacts.sh b/scripts/source/artifacts.sh
index c65e007..5034232 100644
--- a/scripts/source/artifacts.sh
+++ b/scripts/source/artifacts.sh
@@ -108,6 +108,23 @@ lpFetchIndex() {
     return 0
 }
 
+# lpFetchIndexInto <varname> [cache_path] — lpFetchIndex run IN THIS SHELL so
+# the LP_INDEX_SIGSTATE global actually reaches the caller. A plain
+# var="$(lpFetchIndex)" capture strands that assignment in the substitution's
+# subshell: the caller then reads the file-scope "" and the apply-path gate
+# refuses even a correctly signed index. Any caller that inspects
+# LP_INDEX_SIGSTATE after fetching MUST use this wrapper, not $(…).
+lpFetchIndexInto() {
+    local __lpfi_var="$1" __lpfi_tmp __lpfi_rc=0
+    __lpfi_tmp="$(mktemp)"
+    lpFetchIndex "${2:-}" > "$__lpfi_tmp" || __lpfi_rc=$?
+    if (( __lpfi_rc == 0 )); then
+        printf -v "$__lpfi_var" '%s' "$(cat "$__lpfi_tmp")"
+    fi
+    rm -f "$__lpfi_tmp"
+    return "$__lpfi_rc"
+}
+
 # --- Parsing accessors -------------------------------------------------------
 # The trust-critical fields (index_serial / valid_until / signature) are read
 # jq-free above so the security core has no jq dependency. Enumerating the
diff --git a/scripts/source/files/arrays/function_manifest.sh b/scripts/source/files/arrays/function_manifest.sh
index c42c36d..7a7dc00 100644
--- a/scripts/source/files/arrays/function_manifest.sh
+++ b/scripts/source/files/arrays/function_manifest.sh
@@ -596,6 +596,7 @@ declare -gA LP_FN_MAP=(
     [lpArtifactSerialFile]="source/artifacts.sh"
     [_lpDownload]="source/fetch.sh"
     [lpFetchIndex]="source/artifacts.sh"
+    [lpFetchIndexInto]="source/artifacts.sh"
     [lpFetchRelease]="source/fetch.sh"
     [lpFetchSource]="source/fetch.sh"
     [_lpFetchTool]="source/fetch.sh"
@@ -1554,6 +1555,7 @@ declare -gA LP_FN_ROOT=(
     [lpArtifactSerialFile]="scripts"
     [_lpDownload]="scripts"
     [lpFetchIndex]="scripts"
+    [lpFetchIndexInto]="scripts"
     [lpFetchRelease]="scripts"
     [lpFetchSource]="scripts"
     [_lpFetchTool]="scripts"
@@ -2533,6 +2535,7 @@ lpArtifactRecordSerial() { source "${install_scripts_dir}source/artifacts.sh"; l
 lpArtifactSerialFile() { source "${install_scripts_dir}source/artifacts.sh"; lpArtifactSerialFile "$@"; }
 _lpDownload() { source "${install_scripts_dir}source/fetch.sh"; _lpDownload "$@"; }
 lpFetchIndex() { source "${install_scripts_dir}source/artifacts.sh"; lpFetchIndex "$@"; }
+lpFetchIndexInto() { source "${install_scripts_dir}source/artifacts.sh"; lpFetchIndexInto "$@"; }
 lpFetchRelease() { source "${install_scripts_dir}source/fetch.sh"; lpFetchRelease "$@"; }
 lpFetchSource() { source "${install_scripts_dir}source/fetch.sh"; lpFetchSource "$@"; }
 _lpFetchTool() { source "${install_scripts_dir}source/fetch.sh"; _lpFetchTool "$@"; }
diff --git a/scripts/webui/data/generators/updater/webui_artifact_scan.sh b/scripts/webui/data/generators/updater/webui_artifact_scan.sh
index e95200a..84cdc6f 100644
--- a/scripts/webui/data/generators/updater/webui_artifact_scan.sh
+++ b/scripts/webui/data/generators/updater/webui_artifact_scan.sh
@@ -29,7 +29,7 @@ webuiArtifactScan() {
     fi
 
     local index
-    if ! index="$(lpFetchIndex)"; then
+    if ! lpFetchIndexInto index; then
         isNotice "webuiArtifactScan: no verified index available — keeping the prior file."
         return 0
     fi