diff --git a/scripts/post_alert_action.py b/scripts/post_alert_action.py
index d412461..c694e88 100644
--- a/scripts/post_alert_action.py
+++ b/scripts/post_alert_action.py
@@ -42,6 +42,7 @@
 
 BLENDER_NAME = "BLEnder"
 DISMISS_BLOCKED_SEVERITIES = {"critical", "high"}
+DISMISS_UNKNOWN_SEVERITIES = {"", "unknown"}
 VERDICT_FILE = ".blender-alert-verdict.json"
 REQUIRED_KEYS = {
     "affected",
@@ -470,6 +471,14 @@ def main() -> None:
             print(f"  Existing PR #{existing_pr} covers this package.")
             comment_on_pr(repo, existing_pr, reason, dry_run)
             action = "existing_pr"
+        elif (
+            dismiss_enabled
+            and severity.lower() not in DISMISS_BLOCKED_SEVERITIES
+            and severity.lower() not in DISMISS_UNKNOWN_SEVERITIES
+        ):
+            print("  Unaffected + dismiss enabled (low/medium). Dismissing alert.")
+            dismiss_alert(repo, alert_number, reason, dry_run)
+            action = "dismissed"
         elif recommended == "bump_pr":
             if ecosystem == "npm" and patched_version:
                 print("  npm ecosystem — deferring to npm_bump workflow step.")
@@ -511,10 +520,6 @@ def main() -> None:
                             action = "noop"
                     else:
                         action = "noop"
-        elif dismiss_enabled and severity.lower() not in DISMISS_BLOCKED_SEVERITIES:
-            print("  Unaffected + dismiss enabled. Dismissing alert.")
-            dismiss_alert(repo, alert_number, reason, dry_run)
-            action = "dismissed"
         elif dismiss_enabled:
             print(
                 f"  Unaffected but severity is {severity}."
diff --git a/tests/scripts/test_post_alert_action.py b/tests/scripts/test_post_alert_action.py
index cb7f576..4e32bca 100644
--- a/tests/scripts/test_post_alert_action.py
+++ b/tests/scripts/test_post_alert_action.py
@@ -332,6 +332,23 @@ def test_dismiss_skips_high_severity(
 
         mock_repo._requester.requestJsonAndCheck.assert_not_called()
 
+    def test_dismiss_skips_unknown_severity(
+        self, verdict_file, tmp_path, monkeypatch
+    ):
+        """Empty/unknown severity is not auto-dismissed (could be high/critical)."""
+        verdict = {**SAMPLE_VERDICT, "recommended_action": "none"}
+        verdict_file(verdict)
+        mock_repo = MagicMock()
+        mock_repo.full_name = "owner/repo"
+        mock_repo.get_pulls.return_value = []
+
+        self._run_main(
+            verdict_file, tmp_path, monkeypatch, mock_repo,
+            DISMISS_UNAFFECTED="true", ALERT_SEVERITY="",
+        )
+
+        mock_repo._requester.requestJsonAndCheck.assert_not_called()
+
     def test_npm_bump_outputs_action(
         self, verdict_file, tmp_path, monkeypatch
     ):
@@ -363,6 +380,29 @@ def test_npm_bump_outputs_action(
         mock_repo.get_contents.assert_not_called()
         mock_repo.create_pull.assert_not_called()
 
+    def test_dismiss_precedes_npm_bump_for_unaffected(
+        self, verdict_file, tmp_path, monkeypatch
+    ):
+        """Unaffected low/medium alert is dismissed, not routed to npm_bump (#112)."""
+        verdict_file(SAMPLE_VERDICT)  # affected=False, recommended_action=bump_pr
+        mock_repo = MagicMock()
+        mock_repo.full_name = "owner/repo"
+        mock_repo.get_pulls.return_value = []  # no existing PR
+
+        output_file = str(tmp_path / "github_output")
+        open(output_file, "w").close()
+
+        self._run_main(
+            verdict_file, tmp_path, monkeypatch, mock_repo,
+            ALERT_ECOSYSTEM="npm", ALERT_SEVERITY="medium",
+            DISMISS_UNAFFECTED="true", DRY_RUN="true",
+            GITHUB_OUTPUT=output_file,
+        )
+
+        outputs = open(output_file).read()
+        assert "action=dismissed" in outputs
+        assert "action=npm_bump" not in outputs
+
     def test_npm_bump_no_patched_version(
         self, verdict_file, tmp_path, monkeypatch
     ):