diff --git a/scripts/promote-tenant-image.sh b/scripts/promote-tenant-image.sh
index c8b21b8a..279e754d 100755
--- a/scripts/promote-tenant-image.sh
+++ b/scripts/promote-tenant-image.sh
@@ -179,6 +179,7 @@ cp_redeploy_tenant() {
   #   1  — any other failure
   # stdout = response body. stderr = "HTTP_STATUS=NNN" line.
   local slug="$1" tag="$2"
+  validate_slug "$slug"
   _mock_call cp_redeploy_tenant "$slug" "$tag"; local _mrc=$?
   [[ $_mrc -ne 99 ]] && return $_mrc
   local tok="${!CP_TOKEN_ENV:-}"
@@ -204,6 +205,7 @@ cp_redeploy_tenant() {
 tenant_buildinfo() {
   # args: <slug>; prints JSON
   local slug="$1"
+  validate_slug "$slug"
   _mock_call tenant_buildinfo "$slug"; local _mrc=$?
   [[ $_mrc -ne 99 ]] && return $_mrc
   curl -sf --max-time 10 "https://${slug}.moleculesai.app/buildinfo"
@@ -212,6 +214,7 @@ tenant_buildinfo() {
 tenant_health() {
   # args: <slug>; prints raw response, returns 0 if "ok"
   local slug="$1"
+  validate_slug "$slug"
   _mock_call tenant_health "$slug"; local _mrc=$?
   [[ $_mrc -ne 99 ]] && return $_mrc
   curl -sf --max-time 10 "https://${slug}.moleculesai.app/health"
@@ -256,6 +259,7 @@ print(json.dumps({'commands': [ecr_login]}))
 resolve_tenant_instance_id() {
   # args: <slug>; prints i-xxx
   local slug="$1"
+  validate_slug "$slug"
   _mock_call resolve_tenant_instance_id "$slug"; local _mrc=$?
   [[ $_mrc -ne 99 ]] && return $_mrc
   local tok="${!CP_TOKEN_ENV:-}"
@@ -271,6 +275,19 @@ resolve_tenant_instance_id() {
 log() { printf '[%s] %s\n' "$(date -u +%H:%M:%SZ)" "$*"; }
 err() { printf '[%s] ERROR: %s\n' "$(date -u +%H:%M:%SZ)" "$*" >&2; }
 
+# validate_slug — exit 64 if slug contains characters outside the safe set.
+# Prevents SSRF via query-separator injection (?foo) and subdomain takeover
+# (@evil) when slug is interpolated into URL paths or subdomains.
+# OFFSEC-006 fix.
+validate_slug() {
+  local slug="$1"
+  if ! [[ "$slug" =~ ^[a-z0-9]([a-z0-9-]{0,61}[a-z0-9])?$ ]]; then
+    printf '[%s] ERROR: invalid slug: %s\n' \
+      "$(date -u +%H:%M:%SZ)" "$slug" >&2
+    exit 64
+  fi
+}
+
 preflight() {
   log "preflight: source=$SOURCE_TAG dest=$DEST_TAG repo=$REPO region=$REGION"
   local src_manifest
@@ -339,6 +356,7 @@ promote() {
 redeploy_tenant() {
   # args: <slug> — handle the 403→SSM-refresh→retry pattern
   local slug="$1"
+  validate_slug "$slug"
   log "  redeploy: $slug"
   if [[ "$DRY_RUN" == "true" ]]; then
     log "    [dry-run] would POST /redeploy slug=$slug"
@@ -372,6 +390,7 @@ redeploy_tenant() {
 
 verify_tenant() {
   local slug="$1"
+  validate_slug "$slug"
   log "  verify: $slug"
   if [[ "$DRY_RUN" == "true" ]]; then
     log "    [dry-run] would curl /buildinfo + /health"
@@ -398,6 +417,7 @@ rollback() {
   rm -f "$mfile"
   IFS=',' read -ra slugs <<<"$TENANTS"
   for slug in "${slugs[@]}"; do
+    validate_slug "$slug"
     redeploy_tenant "$slug" || err "  rollback redeploy failed for $slug"
   done
   log "rollback: complete"
@@ -408,6 +428,13 @@ rollback() {
 # ─────────────────────────────────────────────────────────────────────────────
 
 main() {
+  # OFFSEC-006: validate slugs before any network I/O.
+  IFS=',' read -ra _slugs <<<"$TENANTS"
+  for _slug in "${_slugs[@]}"; do
+    validate_slug "$_slug"
+  done
+  unset _slugs _slug
+
   preflight || return 1
   snapshot_dest_tag || return 2
   promote || return 2
@@ -415,8 +442,15 @@ main() {
   local promote_rc=0
   IFS=',' read -ra slugs <<<"$TENANTS"
   for slug in "${slugs[@]}"; do
-    redeploy_tenant "$slug" || promote_rc=1
-    [[ $promote_rc -eq 0 ]] && { verify_tenant "$slug" || promote_rc=1; }
+    validate_slug "$slug"
+    if ! redeploy_tenant "$slug"; then
+      promote_rc=1
+    fi
+    if [[ $promote_rc -eq 0 ]]; then
+      if ! verify_tenant "$slug"; then
+        promote_rc=1
+      fi
+    fi
     [[ $promote_rc -ne 0 ]] && break
   done
 
diff --git a/scripts/test-promote-tenant-image.sh b/scripts/test-promote-tenant-image.sh
index eac19195..8a208b64 100644
--- a/scripts/test-promote-tenant-image.sh
+++ b/scripts/test-promote-tenant-image.sh
@@ -267,7 +267,51 @@ else
   printf '  ✗ unknown-flag should fail (got %s)\n' "$rc"
 fi
 
-printf '\n== Test 9: ROLLBACK_TAG follows YYYYMMDD via NOW_OVERRIDE_DATE ==\n'
+printf '\n== Test 9: slug validation — invalid slugs rejected with exit 64 (OFFSEC-006) ==\n'
+# Attack vectors: SSRF via ? (curl query separator), subdomain takeover via @,
+# path traversal via /, shell metacharacters.  Use a newline-delimited temp file
+# so slugs containing spaces are NOT split by shell word-splitting.
+_invalid_tmp=$(mktemp)
+cat > "$_invalid_tmp" <<'INVALID_EOF'
+a?url=https://evil.com
+a&url=https://evil.com
+a@evil.com
+a/b
+a\b
+a b
+chloe-dong?url=http://evil.com
+evil.com@legitimate
+INVALID_EOF
+while IFS= read -r attack || [[ -n "$attack" ]]; do
+  set +e
+  out=$("$SCRIPT" --source-tag x --dest-tag y --tenants "$attack" 2>&1); rc=$?
+  set -e
+  if [[ $rc -eq 64 ]] && printf '%s' "$out" | grep -q 'invalid slug'; then
+    PASS=$((PASS + 1)); printf '  ✓ slug rejected: %s\n' "$(printf '%q' "$attack")"
+  else
+    FAIL=$((FAIL + 1)); FAIL_NAMES+=("slug-reject:$attack")
+    printf '  ✗ slug should be rejected: %s — got exit %s\n' "$(printf '%q' "$attack")" "$rc"
+  fi
+done < "$_invalid_tmp"
+rm -f "$_invalid_tmp"
+
+printf '\n== Test 10: slug validation — valid slugs pass through ==\n'
+valid_slugs='chloe-dong hongming ab a abc123 my-tenant-42'
+for slug in $valid_slugs; do
+  set +e
+  out=$("$SCRIPT" --source-tag x --dest-tag y --tenants "$slug" --mock-dir /nonexistent 2>&1); rc=$?
+  set -e
+  # valid slugs: script should fail at preflight (no such mock dir / no real infra),
+  # but NOT at slug validation (exit 64). So we check exit != 64.
+  if [[ $rc -ne 64 ]]; then
+    PASS=$((PASS + 1)); printf '  ✓ valid slug accepted: %s\n' "$slug"
+  else
+    FAIL=$((FAIL + 1)); FAIL_NAMES+=("slug-accept:$slug")
+    printf '  ✗ valid slug rejected: %s (should have passed slug check)\n' "$slug"
+  fi
+done
+
+printf '\n== Test 11: ROLLBACK_TAG follows YYYYMMDD via NOW_OVERRIDE_DATE ==\n'
 m=$(mkmock)
 mock_set "$m" aws_ecr_get_image       '{}' 0
 mock_set "$m" aws_ecr_describe_image  '' 1
@@ -289,7 +333,7 @@ fi
 assert_calls_contain "rollback tag uses NOW_OVERRIDE_DATE (20260603)" "$m" 'aws_ecr_put_image b-prev-20260603'
 rm -rf "$m"
 
-printf '\n== Test 10: empty source manifest fails preflight ==\n'
+printf '\n== Test 12: empty source manifest fails preflight ==\n'
 m=$(mkmock)
 mock_set "$m" aws_ecr_get_image '' 0   # rc=0 but empty body (the "None" case)
 out=$(run_script "$m")
@@ -297,7 +341,7 @@ assert_exit "empty source manifest fails preflight" "$out" 1
 assert_contains "empty manifest message" "$out" 'returned empty manifest'
 rm -rf "$m"
 
-printf '\n== Test 11: tenant_buildinfo failure during verify → rollback ==\n'
+printf '\n== Test 13: tenant_buildinfo failure during verify → rollback ==\n'
 m=$(mkmock)
 mock_set "$m" aws_ecr_get_image          '{"manifests":[]}' 0
 mock_set "$m" aws_ecr_describe_image     '' 1
@@ -311,7 +355,7 @@ assert_contains "logs buildinfo failure" "$out" '/buildinfo failed for chloe-don
 assert_contains "rollback fired after verify fail" "$out" 'ROLLBACK:'
 rm -rf "$m"
 
-printf '\n== Test 12: ssm_refresh_ecr_auth JSON escaping (CWE-78 / OFFSEC-001) ==\n'
+printf '\n== Test 14: ssm_refresh_ecr_auth JSON escaping (CWE-78 / OFFSEC-001) ==\n'
 # Verify the python3 snippet in ssm_refresh_ecr_auth produces valid JSON and
 # correctly escapes shell-injection characters in region + account ID fields.
 # The fix replaces unquoted shell-printf interpolation with json.dumps.