diff --git a/server/src/plugins/service-admin-http/html-response.ts b/server/src/plugins/service-admin-http/html-response.ts
index 2be3b39..6cc4d0f 100644
--- a/server/src/plugins/service-admin-http/html-response.ts
+++ b/server/src/plugins/service-admin-http/html-response.ts
@@ -5,17 +5,35 @@
  * a string/object directly. This helper wraps JSX output in a
  * proper Response with text/html content type.
  */
+/**
+ * Baseline security headers. CSP keeps 'unsafe-inline' for scripts because
+ * jsx-htmx's js() helper emits inline <script> blocks and htmx uses inline
+ * event handler attributes; tightening this needs per-render nonces.
+ */
+const SECURITY_HEADERS = {
+  "content-type": "text/html; charset=utf-8",
+  "content-security-policy":
+    "default-src 'self'; " +
+    "img-src 'self' data: blob:; " +
+    "script-src 'self' 'unsafe-inline'; " +
+    "style-src 'self' 'unsafe-inline'; " +
+    "frame-src 'self'; " +
+    "frame-ancestors 'none'; " +
+    "base-uri 'self'; " +
+    "form-action 'self'",
+  "x-frame-options": "DENY",
+  "x-content-type-options": "nosniff",
+  "referrer-policy": "strict-origin-when-cross-origin",
+  "strict-transport-security": "max-age=31536000; includeSubDomains",
+} as const;
+
 export function htmlPage(markup: unknown): Response {
-  return new Response(String(markup), {
-    headers: { "content-type": "text/html; charset=utf-8" },
-  });
+  return new Response(String(markup), { headers: SECURITY_HEADERS });
 }
 
 /** Same as htmlPage — separate name for htmx fragment swaps to read clearly. */
 export function htmlFragment(markup: unknown): Response {
-  return new Response(String(markup), {
-    headers: { "content-type": "text/html; charset=utf-8" },
-  });
+  return new Response(String(markup), { headers: SECURITY_HEADERS });
 }
 
 /**
diff --git a/server/src/plugins/service-admin-http/routes-auth.ts b/server/src/plugins/service-admin-http/routes-auth.ts
index 0e8bc93..6804ece 100644
--- a/server/src/plugins/service-admin-http/routes-auth.ts
+++ b/server/src/plugins/service-admin-http/routes-auth.ts
@@ -6,6 +6,11 @@ import { htmlPage, redirectWithCookie, redirectClearCookie } from "./html-respon
 import type { AdminDeps } from "./index.js";
 import { LoginPage, TotpPage, RecoveryPage } from "../../web-templates/auth-pages.js";
 import { audit } from "../../shared/audit.js";
+import { createRateLimiter } from "../../shared/rate-limit.js";
+
+// 8 attempts per 60s per IP — paired with the user-account lockout already in
+// place via deps.auth.config.loginLockoutThreshold to defeat enumeration.
+const loginGuard = createRateLimiter({ windowMs: 60_000, max: 8 });
 
 
 export function registerAuthRoutes(app: H3, deps: AdminDeps): void {
@@ -18,6 +23,20 @@ export function registerAuthRoutes(app: H3, deps: AdminDeps): void {
   });
 
   app.post("/auth/login", async (event) => {
+    const ip = getRequestHeader(event, "x-real-ip")
+      ?? getRequestHeader(event, "x-forwarded-for")?.split(",")[0]?.trim()
+      ?? "anon";
+    if (!loginGuard.take(`login:${ip}`)) {
+      audit(deps.repo, event as any, "user.login", {
+        result: "failed",
+        metadata: { reason: "rate_limited", ip },
+      });
+      return new Response("Too many login attempts. Try again in a minute.", {
+        status: 429,
+        headers: { "retry-after": "60", "content-type": "text/plain" },
+      });
+    }
+
     const body = await readBody<{ username?: string; password?: string }>(event);
     const username = (body?.username ?? "").trim();
     const password = body?.password ?? "";
diff --git a/server/src/plugins/service-api-http/index.ts b/server/src/plugins/service-api-http/index.ts
index fc571aa..cef38f5 100644
--- a/server/src/plugins/service-api-http/index.ts
+++ b/server/src/plugins/service-api-http/index.ts
@@ -23,7 +23,13 @@ import { generateBundle } from "../../shared/bundle.js";
 import { initNoderedBridge, type NoderedBridge } from "../../shared/nodered-bridge.js";
 import { initFirmware, type FirmwareApi } from "../../shared/firmware.js";
 import { envStr } from "../../shared/env-overrides.js";
+import { createRateLimiter } from "../../shared/rate-limit.js";
 import { createHash } from "node:crypto";
+
+// Pairing initiation is unauth — guard it so a misbehaving kiosk or attacker
+// can't spam codes. 20 per minute per IP is generous for legit retries.
+const pairingGuard = createRateLimiter({ windowMs: 60_000, max: 20 });
+const claimGuard = createRateLimiter({ windowMs: 60_000, max: 60 });
 import type { Repository } from "../service-store/repository.js";
 import type { AuthApi } from "../../shared/auth.js";
 import type { SecretsApi } from "../../shared/secrets.js";
@@ -194,6 +200,13 @@ function registerPairingRoutes(
 ): void {
   // Kiosk initiates pairing — no auth required
   app.post("/api/pair/initiate", async (event) => {
+    const ip = getRequestHeader(event, "x-real-ip")
+      ?? getRequestHeader(event, "x-forwarded-for")?.split(",")[0]?.trim()
+      ?? "anon";
+    if (!pairingGuard.take(`pair:${ip}`)) {
+      throw createError({ statusCode: 429, statusMessage: "rate limited" });
+    }
+
     const body = await readBody<{
       proposed_name?: string;
       hardware_model?: string;
@@ -212,6 +225,13 @@ function registerPairingRoutes(
 
   // Kiosk polls for claim result — no auth required
   app.post("/api/pair/claim", async (event) => {
+    const ip = getRequestHeader(event, "x-real-ip")
+      ?? getRequestHeader(event, "x-forwarded-for")?.split(",")[0]?.trim()
+      ?? "anon";
+    if (!claimGuard.take(`claim:${ip}`)) {
+      throw createError({ statusCode: 429, statusMessage: "rate limited" });
+    }
+
     const body = await readBody<{ code?: string }>(event);
     const code = (body?.code ?? "").trim().toUpperCase();
     if (!code) throw createError({ statusCode: 400, statusMessage: "code required" });
diff --git a/server/src/shared/rate-limit.ts b/server/src/shared/rate-limit.ts
new file mode 100644
index 0000000..cbc5012
--- /dev/null
+++ b/server/src/shared/rate-limit.ts
@@ -0,0 +1,57 @@
+/**
+ * In-memory sliding-window rate limiter. Per-key bucket holds timestamps of
+ * recent hits; we trim entries older than the window on every check.
+ *
+ * Suits single-process BSB; if we scale horizontally later swap in Redis.
+ *
+ *   const guard = createRateLimiter({ windowMs: 60_000, max: 5 });
+ *   if (guard.take(`login:${ip}`)) ... // false = rate-limited
+ */
+
+export interface RateLimitConfig {
+  windowMs: number;
+  max: number;
+}
+
+export interface RateLimiter {
+  /** Returns true if allowed, false if over limit. */
+  take(key: string): boolean;
+  /** How many hits remain in the current window for this key. */
+  remaining(key: string): number;
+  /** Clear a specific key (e.g. after a successful auth). */
+  reset(key: string): void;
+}
+
+export function createRateLimiter(config: RateLimitConfig): RateLimiter {
+  const buckets = new Map<string, number[]>();
+
+  function trim(key: string, now: number): number[] {
+    const cutoff = now - config.windowMs;
+    const arr = buckets.get(key) ?? [];
+    const filtered = arr.filter((ts) => ts >= cutoff);
+    if (filtered.length === 0) {
+      buckets.delete(key);
+    } else {
+      buckets.set(key, filtered);
+    }
+    return filtered;
+  }
+
+  return {
+    take(key: string): boolean {
+      const now = Date.now();
+      const arr = trim(key, now);
+      if (arr.length >= config.max) return false;
+      arr.push(now);
+      buckets.set(key, arr);
+      return true;
+    },
+    remaining(key: string): number {
+      const arr = trim(key, Date.now());
+      return Math.max(0, config.max - arr.length);
+    },
+    reset(key: string): void {
+      buckets.delete(key);
+    },
+  };
+}