diff --git a/CHANGELOG.md b/CHANGELOG.md
index 348e55682f9..e54aceb118f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -22,6 +22,7 @@ Docs: https://docs.openclaw.ai
 - Sessions/Store: canonicalize inbound mixed-case session keys for metadata and route updates, and migrate legacy case-variant entries to a single lowercase key to prevent duplicate sessions and missing TUI/WebUI history. (#9561) Thanks @hillghost86.
 - Security/CI: add pre-commit security hook coverage for private-key detection and production dependency auditing, and enforce those checks in CI alongside baseline secret scanning. Thanks @vincentkoc.
 - Skills/Python: harden skill script packaging and validation edge cases (self-including `.skill` outputs, CRLF frontmatter parsing, strict `--days` validation, and safer image file loading), with expanded Python regression coverage. Thanks @vincentkoc.
+- Config/Write: apply `unsetPaths` with immutable path-copy updates so config writes never mutate caller-provided objects, and harden `openclaw config get/set/unset` path traversal by rejecting prototype-key segments and inherited-property traversal. (#24134) thanks @frankekn.
 
 ## 2026.2.23
 
diff --git a/src/cli/config-cli.test.ts b/src/cli/config-cli.test.ts
index 392be2ad0cc..a1735449736 100644
--- a/src/cli/config-cli.test.ts
+++ b/src/cli/config-cli.test.ts
@@ -204,6 +204,35 @@ describe("config cli", () => {
     });
   });
 
+  describe("path hardening", () => {
+    it("rejects blocked prototype-key segments for config get", async () => {
+      await expect(runConfigCommand(["config", "get", "gateway.__proto__.token"])).rejects.toThrow(
+        "Invalid path segment: __proto__",
+      );
+
+      expect(mockReadConfigFileSnapshot).not.toHaveBeenCalled();
+      expect(mockWriteConfigFile).not.toHaveBeenCalled();
+    });
+
+    it("rejects blocked prototype-key segments for config set", async () => {
+      await expect(
+        runConfigCommand(["config", "set", "tools.constructor.profile", '"sandbox"']),
+      ).rejects.toThrow("Invalid path segment: constructor");
+
+      expect(mockReadConfigFileSnapshot).not.toHaveBeenCalled();
+      expect(mockWriteConfigFile).not.toHaveBeenCalled();
+    });
+
+    it("rejects blocked prototype-key segments for config unset", async () => {
+      await expect(
+        runConfigCommand(["config", "unset", "channels.prototype.enabled"]),
+      ).rejects.toThrow("Invalid path segment: prototype");
+
+      expect(mockReadConfigFileSnapshot).not.toHaveBeenCalled();
+      expect(mockWriteConfigFile).not.toHaveBeenCalled();
+    });
+  });
+
   describe("config unset - issue #6070", () => {
     it("preserves existing config keys when unsetting a value", async () => {
       const resolved: OpenClawConfig = {
diff --git a/src/cli/config-cli.ts b/src/cli/config-cli.ts
index c9fb6e33520..3893aa1d020 100644
--- a/src/cli/config-cli.ts
+++ b/src/cli/config-cli.ts
@@ -1,6 +1,7 @@
 import type { Command } from "commander";
 import JSON5 from "json5";
 import { readConfigFileSnapshot, writeConfigFile } from "../config/config.js";
+import { isBlockedObjectKey } from "../config/prototype-keys.js";
 import { redactConfigObject } from "../config/redact-snapshot.js";
 import { danger, info } from "../globals.js";
 import type { RuntimeEnv } from "../runtime.js";
@@ -88,6 +89,18 @@ function parseValue(raw: string, opts: ConfigSetParseOpts): unknown {
   }
 }
 
+function hasOwnPathKey(value: Record<string, unknown>, key: string): boolean {
+  return Object.prototype.hasOwnProperty.call(value, key);
+}
+
+function validatePathSegments(path: PathSegment[]): void {
+  for (const segment of path) {
+    if (!isIndexSegment(segment) && isBlockedObjectKey(segment)) {
+      throw new Error(`Invalid path segment: ${segment}`);
+    }
+  }
+}
+
 function getAtPath(root: unknown, path: PathSegment[]): { found: boolean; value?: unknown } {
   let current: unknown = root;
   for (const segment of path) {
@@ -106,7 +119,7 @@ function getAtPath(root: unknown, path: PathSegment[]): { found: boolean; value?
       continue;
     }
     const record = current as Record<string, unknown>;
-    if (!(segment in record)) {
+    if (!hasOwnPathKey(record, segment)) {
       return { found: false };
     }
     current = record[segment];
@@ -136,7 +149,7 @@ function setAtPath(root: Record<string, unknown>, path: PathSegment[], value: un
       throw new Error(`Cannot traverse into "${segment}" (not an object)`);
     }
     const record = current as Record<string, unknown>;
-    const existing = record[segment];
+    const existing = hasOwnPathKey(record, segment) ? record[segment] : undefined;
     if (!existing || typeof existing !== "object") {
       record[segment] = nextIsIndex ? [] : {};
     }
@@ -177,7 +190,7 @@ function unsetAtPath(root: Record<string, unknown>, path: PathSegment[]): boolea
       continue;
     }
     const record = current as Record<string, unknown>;
-    if (!(segment in record)) {
+    if (!hasOwnPathKey(record, segment)) {
       return false;
     }
     current = record[segment];
@@ -199,7 +212,7 @@ function unsetAtPath(root: Record<string, unknown>, path: PathSegment[]): boolea
     return false;
   }
   const record = current as Record<string, unknown>;
-  if (!(last in record)) {
+  if (!hasOwnPathKey(record, last)) {
     return false;
   }
   delete record[last];
@@ -225,6 +238,7 @@ function parseRequiredPath(path: string): PathSegment[] {
   if (parsedPath.length === 0) {
     throw new Error("Path is empty.");
   }
+  validatePathSegments(parsedPath);
   return parsedPath;
 }
 
@@ -322,10 +336,7 @@ export function registerConfigCli(program: Command) {
     .option("--json", "Legacy alias for --strict-json", false)
     .action(async (path: string, value: string, opts) => {
       try {
-        const parsedPath = parsePath(path);
-        if (parsedPath.length === 0) {
-          throw new Error("Path is empty.");
-        }
+        const parsedPath = parseRequiredPath(path);
         const parsedValue = parseValue(value, {
           strictJson: Boolean(opts.strictJson || opts.json),
         });
diff --git a/src/config/io.ts b/src/config/io.ts
index fba3be8d63f..574b52ee293 100644
--- a/src/config/io.ts
+++ b/src/config/io.ts
@@ -39,6 +39,7 @@ import { applyMergePatch } from "./merge-patch.js";
 import { normalizeExecSafeBinProfilesInConfig } from "./normalize-exec-safe-bin.js";
 import { normalizeConfigPaths } from "./normalize-paths.js";
 import { resolveConfigPath, resolveDefaultConfigCandidates, resolveStateDir } from "./paths.js";
+import { isBlockedObjectKey } from "./prototype-keys.js";
 import { applyConfigOverrides } from "./runtime-overrides.js";
 import type { OpenClawConfig, ConfigFileSnapshot, LegacyConfigIssue } from "./types.js";
 import {
@@ -143,76 +144,104 @@ function isWritePlainObject(value: unknown): value is Record<string, unknown> {
   return Boolean(value) && typeof value === "object" && !Array.isArray(value);
 }
 
-function unsetPathForWrite(root: Record<string, unknown>, pathSegments: string[]): boolean {
-  if (pathSegments.length === 0) {
-    return false;
+function hasOwnObjectKey(value: Record<string, unknown>, key: string): boolean {
+  return Object.prototype.hasOwnProperty.call(value, key);
+}
+
+const WRITE_PRUNED_OBJECT = Symbol("write-pruned-object");
+
+type UnsetPathWriteResult = {
+  changed: boolean;
+  value: unknown;
+};
+
+function unsetPathForWriteAt(
+  value: unknown,
+  pathSegments: string[],
+  depth: number,
+): UnsetPathWriteResult {
+  if (depth >= pathSegments.length) {
+    return { changed: false, value };
   }
+  const segment = pathSegments[depth];
+  const isLeaf = depth === pathSegments.length - 1;
 
-  const traversal: Array<{ container: unknown; key: string | number }> = [];
-  let cursor: unknown = root;
-
-  for (let i = 0; i < pathSegments.length - 1; i += 1) {
-    const segment = pathSegments[i];
-    if (Array.isArray(cursor)) {
-      if (!isNumericPathSegment(segment)) {
-        return false;
-      }
-      const index = Number.parseInt(segment, 10);
-      if (!Number.isFinite(index) || index < 0 || index >= cursor.length) {
-        return false;
-      }
-      traversal.push({ container: cursor, key: index });
-      cursor = cursor[index];
-      continue;
+  if (Array.isArray(value)) {
+    if (!isNumericPathSegment(segment)) {
+      return { changed: false, value };
     }
-    if (!isWritePlainObject(cursor) || !(segment in cursor)) {
-      return false;
+    const index = Number.parseInt(segment, 10);
+    if (!Number.isFinite(index) || index < 0 || index >= value.length) {
+      return { changed: false, value };
     }
-    traversal.push({ container: cursor, key: segment });
-    cursor = cursor[segment];
-  }
-
-  const leaf = pathSegments[pathSegments.length - 1];
-  if (Array.isArray(cursor)) {
-    if (!isNumericPathSegment(leaf)) {
-      return false;
+    if (isLeaf) {
+      const next = value.slice();
+      next.splice(index, 1);
+      return { changed: true, value: next };
     }
-    const index = Number.parseInt(leaf, 10);
-    if (!Number.isFinite(index) || index < 0 || index >= cursor.length) {
-      return false;
+    const child = unsetPathForWriteAt(value[index], pathSegments, depth + 1);
+    if (!child.changed) {
+      return { changed: false, value };
     }
-    cursor.splice(index, 1);
-  } else {
-    if (!isWritePlainObject(cursor) || !(leaf in cursor)) {
-      return false;
-    }
-    delete cursor[leaf];
-  }
-
-  // Prune now-empty object branches after unsetting to avoid dead config scaffolding.
-  for (let i = traversal.length - 1; i >= 0; i -= 1) {
-    const { container, key } = traversal[i];
-    let child: unknown;
-    if (Array.isArray(container)) {
-      child = typeof key === "number" ? container[key] : undefined;
-    } else if (isWritePlainObject(container)) {
-      child = container[String(key)];
+    const next = value.slice();
+    if (child.value === WRITE_PRUNED_OBJECT) {
+      next.splice(index, 1);
     } else {
-      break;
-    }
-    if (!isWritePlainObject(child) || Object.keys(child).length > 0) {
-      break;
-    }
-    if (Array.isArray(container) && typeof key === "number") {
-      if (key >= 0 && key < container.length) {
-        container.splice(key, 1);
-      }
-    } else if (isWritePlainObject(container)) {
-      delete container[String(key)];
+      next[index] = child.value;
     }
+    return { changed: true, value: next };
   }
 
-  return true;
+  if (
+    isBlockedObjectKey(segment) ||
+    !isWritePlainObject(value) ||
+    !hasOwnObjectKey(value, segment)
+  ) {
+    return { changed: false, value };
+  }
+  if (isLeaf) {
+    const next: Record<string, unknown> = { ...value };
+    delete next[segment];
+    return {
+      changed: true,
+      value: Object.keys(next).length === 0 ? WRITE_PRUNED_OBJECT : next,
+    };
+  }
+
+  const child = unsetPathForWriteAt(value[segment], pathSegments, depth + 1);
+  if (!child.changed) {
+    return { changed: false, value };
+  }
+  const next: Record<string, unknown> = { ...value };
+  if (child.value === WRITE_PRUNED_OBJECT) {
+    delete next[segment];
+  } else {
+    next[segment] = child.value;
+  }
+  return {
+    changed: true,
+    value: Object.keys(next).length === 0 ? WRITE_PRUNED_OBJECT : next,
+  };
+}
+
+function unsetPathForWrite(
+  root: OpenClawConfig,
+  pathSegments: string[],
+): { changed: boolean; next: OpenClawConfig } {
+  if (pathSegments.length === 0) {
+    return { changed: false, next: root };
+  }
+  const result = unsetPathForWriteAt(root, pathSegments, 0);
+  if (!result.changed) {
+    return { changed: false, next: root };
+  }
+  if (result.value === WRITE_PRUNED_OBJECT) {
+    return { changed: true, next: {} };
+  }
+  if (isWritePlainObject(result.value)) {
+    return { changed: true, next: coerceConfig(result.value) };
+  }
+  return { changed: false, next: root };
 }
 
 export function resolveConfigSnapshotHash(snapshot: {
@@ -1011,16 +1040,20 @@ export function createConfigIO(overrides: ConfigIoDeps = {}) {
 
     const dir = path.dirname(configPath);
     await deps.fs.promises.mkdir(dir, { recursive: true, mode: 0o700 });
-    const outputConfig =
+    const outputConfigBase =
       envRefMap && changedPaths
         ? (restoreEnvRefsFromMap(cfgToWrite, "", envRefMap, changedPaths) as OpenClawConfig)
         : cfgToWrite;
+    let outputConfig = outputConfigBase;
     if (options.unsetPaths?.length) {
       for (const unsetPath of options.unsetPaths) {
         if (!Array.isArray(unsetPath) || unsetPath.length === 0) {
           continue;
         }
-        unsetPathForWrite(outputConfig as Record<string, unknown>, unsetPath);
+        const unsetResult = unsetPathForWrite(outputConfig, unsetPath);
+        if (unsetResult.changed) {
+          outputConfig = unsetResult.next;
+        }
       }
     }
     // Do NOT apply runtime defaults when writing — user config should only contain
diff --git a/src/config/io.write-config.test.ts b/src/config/io.write-config.test.ts
index 110d81ef61e..17f1951de33 100644
--- a/src/config/io.write-config.test.ts
+++ b/src/config/io.write-config.test.ts
@@ -124,6 +124,130 @@ describe("config io write", () => {
     });
   });
 
+  it("does not mutate caller config when unsetPaths is applied on first write", async () => {
+    await withTempHome("openclaw-config-io-", async (home) => {
+      const configPath = path.join(home, ".openclaw", "openclaw.json");
+      const io = createConfigIO({
+        env: {} as NodeJS.ProcessEnv,
+        homedir: () => home,
+        logger: silentLogger,
+      });
+
+      const input: Record<string, unknown> = {
+        gateway: { mode: "local" },
+        commands: { ownerDisplay: "hash" },
+      };
+
+      await io.writeConfigFile(input, { unsetPaths: [["commands", "ownerDisplay"]] });
+
+      expect(input).toEqual({
+        gateway: { mode: "local" },
+        commands: { ownerDisplay: "hash" },
+      });
+      expect((input.commands as Record<string, unknown>).ownerDisplay).toBe("hash");
+      const persisted = JSON.parse(await fs.readFile(configPath, "utf-8")) as {
+        commands?: Record<string, unknown>;
+      };
+      expect(persisted.commands ?? {}).not.toHaveProperty("ownerDisplay");
+    });
+  });
+
+  it("does not mutate caller config when unsetPaths is applied on existing files", async () => {
+    await withTempHome("openclaw-config-io-", async (home) => {
+      const { configPath, io, snapshot } = await writeConfigAndCreateIo({
+        home,
+        initialConfig: {
+          gateway: { mode: "local" },
+          commands: { ownerDisplay: "hash" },
+        },
+      });
+
+      const input = structuredClone(snapshot.config) as Record<string, unknown>;
+      await io.writeConfigFile(input, { unsetPaths: [["commands", "ownerDisplay"]] });
+
+      expect((input.commands as Record<string, unknown>).ownerDisplay).toBe("hash");
+      const persisted = JSON.parse(await fs.readFile(configPath, "utf-8")) as {
+        commands?: Record<string, unknown>;
+      };
+      expect(persisted.commands ?? {}).not.toHaveProperty("ownerDisplay");
+    });
+  });
+
+  it("keeps caller arrays immutable when unsetting array entries", async () => {
+    await withTempHome("openclaw-config-io-", async (home) => {
+      const { configPath, io, snapshot } = await writeConfigAndCreateIo({
+        home,
+        initialConfig: {
+          gateway: { mode: "local" },
+          tools: { alsoAllow: ["exec", "fetch", "read"] },
+        },
+      });
+
+      const input = structuredClone(snapshot.config) as Record<string, unknown>;
+      await io.writeConfigFile(input, { unsetPaths: [["tools", "alsoAllow", "1"]] });
+
+      expect((input.tools as { alsoAllow: string[] }).alsoAllow).toEqual(["exec", "fetch", "read"]);
+      const persisted = JSON.parse(await fs.readFile(configPath, "utf-8")) as {
+        tools?: { alsoAllow?: string[] };
+      };
+      expect(persisted.tools?.alsoAllow).toEqual(["exec", "read"]);
+    });
+  });
+
+  it("treats missing unset paths as no-op without mutating caller config", async () => {
+    await withTempHome("openclaw-config-io-", async (home) => {
+      const { configPath, io } = await writeConfigAndCreateIo({
+        home,
+        initialConfig: {
+          gateway: { mode: "local" },
+          commands: { ownerDisplay: "hash" },
+        },
+      });
+
+      const input: Record<string, unknown> = {
+        gateway: { mode: "local" },
+        commands: { ownerDisplay: "hash" },
+      };
+      await io.writeConfigFile(input, { unsetPaths: [["commands", "missingKey"]] });
+
+      expect((input.commands as Record<string, unknown>).ownerDisplay).toBe("hash");
+      const persisted = JSON.parse(await fs.readFile(configPath, "utf-8")) as {
+        commands?: Record<string, unknown>;
+      };
+      expect(persisted.commands?.ownerDisplay).toBe("hash");
+    });
+  });
+
+  it("ignores blocked prototype-key unset path segments", async () => {
+    await withTempHome("openclaw-config-io-", async (home) => {
+      const { configPath, io } = await writeConfigAndCreateIo({
+        home,
+        initialConfig: {
+          gateway: { mode: "local" },
+          commands: { ownerDisplay: "hash" },
+        },
+      });
+
+      const input: Record<string, unknown> = {
+        gateway: { mode: "local" },
+        commands: { ownerDisplay: "hash" },
+      };
+      await io.writeConfigFile(input, {
+        unsetPaths: [
+          ["commands", "__proto__"],
+          ["commands", "constructor"],
+          ["commands", "prototype"],
+        ],
+      });
+
+      expect((input.commands as Record<string, unknown>).ownerDisplay).toBe("hash");
+      const persisted = JSON.parse(await fs.readFile(configPath, "utf-8")) as {
+        commands?: Record<string, unknown>;
+      };
+      expect(persisted.commands?.ownerDisplay).toBe("hash");
+    });
+  });
+
   it("preserves env var references when writing", async () => {
     await withTempHome("openclaw-config-io-", async (home) => {
       const { configPath, io, snapshot } = await writeConfigAndCreateIo({