diff --git a/CHANGELOG.md b/CHANGELOG.md
index d0412abba26..03d7e298131 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -24,6 +24,7 @@ Docs: https://docs.openclaw.ai
 
 - fix(infra): block ambient Homebrew env vars from brew resolution. (#74463) Thanks @pgondhi987.
 - Thinking/providers: resolve bundled provider thinking profiles through lightweight provider policy artifacts when startup-lazy providers are not active, so OpenAI Codex GPT-5.x keeps xhigh available in Gateway session validation. Fixes #74796. Thanks @maxschachere.
+- Security/Windows: ignore workspace `.env` system-path variables and resolve stale-process `taskkill.exe` from the validated Windows install root, preventing repository-local env files from redirecting cleanup helpers. Thanks @pgondhi987.
 - Plugins/TTS: keep bundled speech-provider discovery available on cold package Gateway paths and add bundled plugin matrix runtime probes for health, readiness, RPC, TTS discovery, and post-ready runtime-deps watchdog coverage. Refs #75283. Thanks @vincentkoc.
 - Google Meet/Twilio: show delegated voice call ID, DTMF, and intro-greeting state in `googlemeet doctor`, and avoid claiming DTMF was sent when no Meet PIN sequence was configured. Refs #72478. Thanks @DougButdorf.
 - Voice Call/Twilio: send notify-mode initial TwiML directly in the outbound create-call request while keeping conversation and pre-connect DTMF calls webhook-driven, so one-shot notify calls do not depend on a first-answer webhook fetch. Supersedes #72758. Thanks @tyshepps.
diff --git a/src/agents/pi-project-settings.test.ts b/src/agents/pi-project-settings.test.ts
index e79779ef97d..f69ecba1cb4 100644
--- a/src/agents/pi-project-settings.test.ts
+++ b/src/agents/pi-project-settings.test.ts
@@ -1,9 +1,13 @@
+import fs from "node:fs/promises";
+import os from "node:os";
+import path from "node:path";
 import { describe, expect, it } from "vitest";
 import {
   buildEmbeddedPiSettingsSnapshot,
   DEFAULT_EMBEDDED_PI_PROJECT_SETTINGS_POLICY,
   resolveEmbeddedPiProjectSettingsPolicy,
 } from "./pi-project-settings-snapshot.js";
+import { createPreparedEmbeddedPiSettingsManager } from "./pi-project-settings.js";
 
 type EmbeddedPiSettingsArgs = Parameters<typeof buildEmbeddedPiSettingsSnapshot>[0];
 
@@ -126,3 +130,48 @@ describe("buildEmbeddedPiSettingsSnapshot", () => {
     });
   });
 });
+
+describe("createPreparedEmbeddedPiSettingsManager", () => {
+  it("keeps trusted file-backed settings runtime-scoped after preparation", async () => {
+    const baseDir = await fs.mkdtemp(path.join(os.tmpdir(), "openclaw-pi-settings-"));
+    try {
+      const cwd = path.join(baseDir, "workspace");
+      const agentDir = path.join(baseDir, "agent");
+      const projectSettingsDir = path.join(cwd, ".pi");
+      const agentSettingsPath = path.join(agentDir, "settings.json");
+      await fs.mkdir(projectSettingsDir, { recursive: true });
+      await fs.mkdir(agentDir, { recursive: true });
+      await fs.writeFile(
+        agentSettingsPath,
+        JSON.stringify({ retry: { enabled: true } }, null, 2),
+        "utf8",
+      );
+      await fs.writeFile(
+        path.join(projectSettingsDir, "settings.json"),
+        JSON.stringify({ shellCommandPrefix: "echo trusted &&" }, null, 2),
+        "utf8",
+      );
+
+      const settingsManager = createPreparedEmbeddedPiSettingsManager({
+        cwd,
+        agentDir,
+        cfg: {
+          agents: { defaults: { embeddedPi: { projectSettingsPolicy: "trusted" } } },
+        },
+      });
+
+      expect(settingsManager.getShellCommandPrefix()).toBe("echo trusted &&");
+      expect(settingsManager.getRetryEnabled()).toBe(true);
+
+      settingsManager.setRetryEnabled(false);
+      await settingsManager.flush();
+
+      const diskSettings = JSON.parse(await fs.readFile(agentSettingsPath, "utf8")) as {
+        retry?: { enabled?: boolean };
+      };
+      expect(diskSettings.retry?.enabled).toBe(true);
+    } finally {
+      await fs.rm(baseDir, { recursive: true, force: true });
+    }
+  });
+});
diff --git a/src/agents/pi-project-settings.ts b/src/agents/pi-project-settings.ts
index bb7bd1e7676..3ec7faa1dee 100644
--- a/src/agents/pi-project-settings.ts
+++ b/src/agents/pi-project-settings.ts
@@ -37,6 +37,17 @@ export function createEmbeddedPiSettingsManager(params: {
   return SettingsManager.inMemory(settings);
 }
 
+function createRuntimeEmbeddedPiSettingsManager(settingsManager: SettingsManager): SettingsManager {
+  return SettingsManager.inMemory(
+    buildEmbeddedPiSettingsSnapshot({
+      globalSettings: settingsManager.getGlobalSettings(),
+      pluginSettings: {},
+      projectSettings: settingsManager.getProjectSettings(),
+      policy: "trusted",
+    }),
+  );
+}
+
 export function createPreparedEmbeddedPiSettingsManager(params: {
   cwd: string;
   agentDir: string;
@@ -44,7 +55,9 @@ export function createPreparedEmbeddedPiSettingsManager(params: {
   /** Resolved context window budget so reserve-token floor can be capped for small models. */
   contextTokenBudget?: number;
 }): SettingsManager {
-  const settingsManager = createEmbeddedPiSettingsManager(params);
+  const settingsManager = createRuntimeEmbeddedPiSettingsManager(
+    createEmbeddedPiSettingsManager(params),
+  );
   applyPiCompactionSettingsFromConfig({
     settingsManager,
     cfg: params.cfg,
diff --git a/src/infra/brew.test.ts b/src/infra/brew.test.ts
index fa7a629bb4a..d0af983d9a5 100644
--- a/src/infra/brew.test.ts
+++ b/src/infra/brew.test.ts
@@ -139,6 +139,18 @@ describe("brew helpers", () => {
     });
   });
 
+  it("does not resolve brew from PATH entries", async () => {
+    await withTempDir({ prefix: "openclaw-brew-" }, async (tmp) => {
+      const pathBin = path.join(tmp, "path-bin");
+      const pathBrew = path.join(pathBin, "brew");
+      await writeExecutable(pathBrew);
+
+      const env: NodeJS.ProcessEnv = { PATH: pathBin };
+
+      expect(resolveBrewExecutable({ homeDir: path.join(tmp, "home"), env })).not.toBe(pathBrew);
+    });
+  });
+
   it("always includes the standard macOS brew dirs after linuxbrew candidates", () => {
     const dirs = resolveBrewPathDirs({ homeDir: "/home/test" });
 
diff --git a/src/infra/dotenv.test.ts b/src/infra/dotenv.test.ts
index ef17726deb2..2eb5a990d16 100644
--- a/src/infra/dotenv.test.ts
+++ b/src/infra/dotenv.test.ts
@@ -680,6 +680,14 @@ describe("workspace .env blocklist completeness", () => {
           "OPENCLAW_NODE_EXEC_HOST",
           "OPENCLAW_NODE_EXEC_FALLBACK",
           "OPENCLAW_ALLOW_PROJECT_LOCAL_BIN",
+          "PATH",
+          "HOMEBREW_BREW_FILE",
+          "HOMEBREW_PREFIX",
+          "SystemRoot",
+          "WINDIR",
+          "ProgramFiles",
+          "ProgramFiles(x86)",
+          "ProgramW6432",
           "SYNOLOGY_CHAT_INCOMING_URL",
           "SYNOLOGY_NAS_HOST",
         ];
diff --git a/src/infra/dotenv.ts b/src/infra/dotenv.ts
index c1e42288490..aaf1facc402 100644
--- a/src/infra/dotenv.ts
+++ b/src/infra/dotenv.ts
@@ -74,10 +74,16 @@ const BLOCKED_WORKSPACE_DOTENV_KEYS = new Set([
   "OPENCLAW_STATE_DIR",
   "OPENCLAW_TEST_TAILSCALE_BINARY",
   "PI_CODING_AGENT_DIR",
+  "PATH",
   "PLAYWRIGHT_CHROMIUM_EXECUTABLE_PATH",
+  "PROGRAMFILES",
+  "PROGRAMFILES(X86)",
+  "PROGRAMW6432",
   "SYNOLOGY_CHAT_INCOMING_URL",
   "SYNOLOGY_NAS_HOST",
+  "SYSTEMROOT",
   "UV_PYTHON",
+  "WINDIR",
 ]);
 
 // Block endpoint redirection for any service without overfitting per-provider names.
diff --git a/src/infra/restart-stale-pids.test.ts b/src/infra/restart-stale-pids.test.ts
index 0be731a2b85..56bacb49e64 100644
--- a/src/infra/restart-stale-pids.test.ts
+++ b/src/infra/restart-stale-pids.test.ts
@@ -90,6 +90,15 @@ vi.mock("./windows-port-pids.js", () => ({
     mockReadWindowsProcessArgsResult(pid, timeoutMs),
 }));
 
+vi.mock("./windows-install-roots.js", () => ({
+  getWindowsInstallRoots: () => ({
+    systemRoot: "C:\\Windows",
+    programFiles: "C:\\Program Files",
+    programFilesX86: "C:\\Program Files (x86)",
+    programW6432: null,
+  }),
+}));
+
 import { resolveLsofCommandSync } from "./ports-lsof.js";
 let __testing: typeof import("./restart-stale-pids.js").__testing;
 let cleanStaleGatewayProcessesSync: typeof import("./restart-stale-pids.js").cleanStaleGatewayProcessesSync;
@@ -980,8 +989,10 @@ describe.skipIf(isWindows)("restart-stale-pids", () => {
 
     it("does not report Windows pids as killed when taskkill fails", () => {
       const origDescriptor = Object.getOwnPropertyDescriptor(process, "platform");
+      const originalSystemRoot = process.env.SystemRoot;
       const stalePid = process.pid + 911;
       Object.defineProperty(process, "platform", { value: "win32", configurable: true });
+      process.env.SystemRoot = "C:\\PoisonedWindows";
       try {
         let fakeNow = 0;
         __testing.setDateNowOverride(() => fakeNow);
@@ -1012,12 +1023,17 @@ describe.skipIf(isWindows)("restart-stale-pids", () => {
 
         expect(cleanStaleGatewayProcessesSync()).toEqual([]);
         expect(mockSpawnSync).toHaveBeenCalledWith(
-          expect.stringContaining("taskkill.exe"),
+          "C:\\Windows\\System32\\taskkill.exe",
           ["/T", "/PID", String(stalePid)],
           expect.objectContaining({ timeout: 5000 }),
         );
       } finally {
         __testing.setDateNowOverride(null);
+        if (originalSystemRoot === undefined) {
+          delete process.env.SystemRoot;
+        } else {
+          process.env.SystemRoot = originalSystemRoot;
+        }
         if (origDescriptor) {
           Object.defineProperty(process, "platform", origDescriptor);
         }
@@ -1063,13 +1079,13 @@ describe.skipIf(isWindows)("restart-stale-pids", () => {
         expect(cleanStaleGatewayProcessesSync()).toEqual([]);
         expect(mockSpawnSync).toHaveBeenNthCalledWith(
           1,
-          expect.stringContaining("taskkill.exe"),
+          "C:\\Windows\\System32\\taskkill.exe",
           ["/T", "/PID", String(stalePid)],
           expect.objectContaining({ timeout: 5000 }),
         );
         expect(mockSpawnSync).toHaveBeenNthCalledWith(
           2,
-          expect.stringContaining("taskkill.exe"),
+          "C:\\Windows\\System32\\taskkill.exe",
           ["/F", "/T", "/PID", String(stalePid)],
           expect.objectContaining({ timeout: 5000 }),
         );
diff --git a/src/infra/restart-stale-pids.ts b/src/infra/restart-stale-pids.ts
index e8485d8c7cd..2d4c8b7e882 100644
--- a/src/infra/restart-stale-pids.ts
+++ b/src/infra/restart-stale-pids.ts
@@ -6,6 +6,7 @@ import { createSubsystemLogger } from "../logging/subsystem.js";
 import { normalizeLowercaseStringOrEmpty } from "../shared/string-coerce.js";
 import { isGatewayArgv } from "./gateway-process-argv.js";
 import { resolveLsofCommandSync } from "./ports-lsof.js";
+import { getWindowsInstallRoots } from "./windows-install-roots.js";
 import {
   readWindowsListeningPidsOnPortSync,
   readWindowsListeningPidsResultSync,
@@ -424,8 +425,8 @@ function terminateStaleProcessesSync(pids: number[]): number[] {
  * Sends a graceful taskkill first (/T for tree), waits, then escalates to /F.
  */
 function terminateStaleProcessesWindows(pids: number[]): number[] {
-  const taskkillPath = path.join(
-    process.env.SystemRoot ?? "C:\\Windows",
+  const taskkillPath = path.win32.join(
+    getWindowsInstallRoots().systemRoot,
     "System32",
     "taskkill.exe",
   );