diff --git a/src/agents/sandbox/network-mode.ts b/src/agents/sandbox/network-mode.ts
new file mode 100644
index 00000000000..6fe5ee6ac82
--- /dev/null
+++ b/src/agents/sandbox/network-mode.ts
@@ -0,0 +1,28 @@
+export type NetworkModeBlockReason = "host" | "container_namespace_join";
+
+export function normalizeNetworkMode(network: string | undefined): string | undefined {
+  const normalized = network?.trim().toLowerCase();
+  return normalized || undefined;
+}
+
+export function getBlockedNetworkModeReason(params: {
+  network: string | undefined;
+  allowContainerNamespaceJoin?: boolean;
+}): NetworkModeBlockReason | null {
+  const normalized = normalizeNetworkMode(params.network);
+  if (!normalized) {
+    return null;
+  }
+  if (normalized === "host") {
+    return "host";
+  }
+  if (normalized.startsWith("container:") && params.allowContainerNamespaceJoin !== true) {
+    return "container_namespace_join";
+  }
+  return null;
+}
+
+export function isDangerousNetworkMode(network: string | undefined): boolean {
+  const normalized = normalizeNetworkMode(network);
+  return normalized === "host" || normalized?.startsWith("container:") === true;
+}
diff --git a/src/agents/sandbox/validate-sandbox-security.ts b/src/agents/sandbox/validate-sandbox-security.ts
index 928459836c4..097f883f988 100644
--- a/src/agents/sandbox/validate-sandbox-security.ts
+++ b/src/agents/sandbox/validate-sandbox-security.ts
@@ -11,6 +11,7 @@ import {
   normalizeSandboxHostPath,
   resolveSandboxHostPathViaExistingAncestor,
 } from "./host-paths.js";
+import { getBlockedNetworkModeReason } from "./network-mode.js";
 
 // Targeted denylist: host paths that should never be exposed inside sandbox containers.
 // Exported for reuse in security audit collectors.
@@ -31,7 +32,6 @@ export const BLOCKED_HOST_PATHS = [
   "/run/docker.sock",
 ];
 
-const BLOCKED_NETWORK_MODES = new Set(["host"]);
 const BLOCKED_SECCOMP_PROFILES = new Set(["unconfined"]);
 const BLOCKED_APPARMOR_PROFILES = new Set(["unconfined"]);
 const RESERVED_CONTAINER_TARGET_PATHS = ["/workspace", SANDBOX_AGENT_WORKSPACE_MOUNT];
@@ -284,12 +284,11 @@ export function validateNetworkMode(
   network: string | undefined,
   options?: ValidateNetworkModeOptions,
 ): void {
-  const normalized = network?.trim().toLowerCase();
-  if (!normalized) {
-    return;
-  }
-
-  if (BLOCKED_NETWORK_MODES.has(normalized)) {
+  const blockedReason = getBlockedNetworkModeReason({
+    network,
+    allowContainerNamespaceJoin: options?.allowContainerNamespaceJoin,
+  });
+  if (blockedReason === "host") {
     throw new Error(
       `Sandbox security: network mode "${network}" is blocked. ` +
         'Network "host" mode bypasses container network isolation. ' +
@@ -297,7 +296,7 @@ export function validateNetworkMode(
     );
   }
 
-  if (normalized.startsWith("container:") && options?.allowContainerNamespaceJoin !== true) {
+  if (blockedReason === "container_namespace_join") {
     throw new Error(
       `Sandbox security: network mode "${network}" is blocked by default. ` +
         'Network "container:*" joins another container namespace and bypasses sandbox network isolation. ' +
diff --git a/src/config/config.sandbox-docker.test.ts b/src/config/config.sandbox-docker.test.ts
index 032a68e857b..71b24af01ef 100644
--- a/src/config/config.sandbox-docker.test.ts
+++ b/src/config/config.sandbox-docker.test.ts
@@ -1,5 +1,8 @@
 import { describe, expect, it } from "vitest";
-import { resolveSandboxBrowserConfig } from "../agents/sandbox/config.js";
+import {
+  resolveSandboxBrowserConfig,
+  resolveSandboxDockerConfig,
+} from "../agents/sandbox/config.js";
 import { validateConfigObject } from "./config.js";
 
 describe("sandbox docker config", () => {
@@ -84,6 +87,22 @@ describe("sandbox docker config", () => {
     expect(res.ok).toBe(true);
   });
 
+  it("uses agent override precedence for dangerouslyAllowContainerNamespaceJoin", () => {
+    const inherited = resolveSandboxDockerConfig({
+      scope: "agent",
+      globalDocker: { dangerouslyAllowContainerNamespaceJoin: true },
+      agentDocker: {},
+    });
+    expect(inherited.dangerouslyAllowContainerNamespaceJoin).toBe(true);
+
+    const overridden = resolveSandboxDockerConfig({
+      scope: "agent",
+      globalDocker: { dangerouslyAllowContainerNamespaceJoin: true },
+      agentDocker: { dangerouslyAllowContainerNamespaceJoin: false },
+    });
+    expect(overridden.dangerouslyAllowContainerNamespaceJoin).toBe(false);
+  });
+
   it("rejects seccomp unconfined via Zod schema validation", () => {
     const res = validateConfigObject({
       agents: {
diff --git a/src/config/schema.help.ts b/src/config/schema.help.ts
index a0d464274fd..bac2c2dcae1 100644
--- a/src/config/schema.help.ts
+++ b/src/config/schema.help.ts
@@ -299,6 +299,10 @@ export const FIELD_HELP: Record<string, string> = {
   "agents.defaults.sandbox.browser.network":
     "Docker network for sandbox browser containers (default: openclaw-sandbox-browser). Avoid bridge if you need stricter isolation.",
   "agents.list[].sandbox.browser.network": "Per-agent override for sandbox browser Docker network.",
+  "agents.defaults.sandbox.docker.dangerouslyAllowContainerNamespaceJoin":
+    "DANGEROUS break-glass override that allows sandbox Docker network mode container:<id>. This joins another container namespace and weakens sandbox isolation.",
+  "agents.list[].sandbox.docker.dangerouslyAllowContainerNamespaceJoin":
+    "Per-agent DANGEROUS override for container namespace joins in sandbox Docker network mode.",
   "agents.defaults.sandbox.browser.cdpSourceRange":
     "Optional CIDR allowlist for container-edge CDP ingress (for example 172.21.0.1/32).",
   "agents.list[].sandbox.browser.cdpSourceRange":
diff --git a/src/config/schema.labels.ts b/src/config/schema.labels.ts
index 397376f6e11..f1706d1af7d 100644
--- a/src/config/schema.labels.ts
+++ b/src/config/schema.labels.ts
@@ -405,6 +405,8 @@ export const FIELD_LABELS: Record<string, string> = {
   "agents.defaults.heartbeat.suppressToolErrorWarnings": "Heartbeat Suppress Tool Error Warnings",
   "agents.defaults.sandbox.browser.network": "Sandbox Browser Network",
   "agents.defaults.sandbox.browser.cdpSourceRange": "Sandbox Browser CDP Source Port Range",
+  "agents.defaults.sandbox.docker.dangerouslyAllowContainerNamespaceJoin":
+    "Sandbox Docker Allow Container Namespace Join",
   commands: "Commands",
   "commands.native": "Native Commands",
   "commands.nativeSkills": "Native Skill Commands",
@@ -713,6 +715,8 @@ export const FIELD_LABELS: Record<string, string> = {
     "Agent Heartbeat Suppress Tool Error Warnings",
   "agents.list[].sandbox.browser.network": "Agent Sandbox Browser Network",
   "agents.list[].sandbox.browser.cdpSourceRange": "Agent Sandbox Browser CDP Source Port Range",
+  "agents.list[].sandbox.docker.dangerouslyAllowContainerNamespaceJoin":
+    "Agent Sandbox Docker Allow Container Namespace Join",
   "discovery.mdns.mode": "mDNS Discovery Mode",
   plugins: "Plugins",
   "plugins.enabled": "Enable Plugins",
diff --git a/src/config/zod-schema.agent-runtime.ts b/src/config/zod-schema.agent-runtime.ts
index ca559ce5e94..c477cc1743b 100644
--- a/src/config/zod-schema.agent-runtime.ts
+++ b/src/config/zod-schema.agent-runtime.ts
@@ -1,4 +1,5 @@
 import { z } from "zod";
+import { getBlockedNetworkModeReason } from "../agents/sandbox/network-mode.js";
 import { parseDurationMs } from "../cli/parse-duration.js";
 import { AgentModelSchema } from "./zod-schema.agent-model.js";
 import {
@@ -154,8 +155,11 @@ export const SandboxDockerSchema = z
         }
       }
     }
-    const network = data.network?.trim().toLowerCase();
-    if (network === "host") {
+    const blockedNetworkReason = getBlockedNetworkModeReason({
+      network: data.network,
+      allowContainerNamespaceJoin: data.dangerouslyAllowContainerNamespaceJoin === true,
+    });
+    if (blockedNetworkReason === "host") {
       ctx.addIssue({
         code: z.ZodIssueCode.custom,
         path: ["network"],
@@ -163,7 +167,7 @@ export const SandboxDockerSchema = z
           'Sandbox security: network mode "host" is blocked. Use "bridge" or "none" instead.',
       });
     }
-    if (network?.startsWith("container:") && data.dangerouslyAllowContainerNamespaceJoin !== true) {
+    if (blockedNetworkReason === "container_namespace_join") {
       ctx.addIssue({
         code: z.ZodIssueCode.custom,
         path: ["network"],
@@ -476,11 +480,11 @@ export const AgentSandboxSchema = z
   })
   .strict()
   .superRefine((data, ctx) => {
-    const browserNetwork = data.browser?.network?.trim().toLowerCase();
-    if (
-      browserNetwork?.startsWith("container:") &&
-      data.docker?.dangerouslyAllowContainerNamespaceJoin !== true
-    ) {
+    const blockedBrowserNetworkReason = getBlockedNetworkModeReason({
+      network: data.browser?.network,
+      allowContainerNamespaceJoin: data.docker?.dangerouslyAllowContainerNamespaceJoin === true,
+    });
+    if (blockedBrowserNetworkReason === "container_namespace_join") {
       ctx.addIssue({
         code: z.ZodIssueCode.custom,
         path: ["browser", "network"],
diff --git a/src/security/audit-extra.sync.ts b/src/security/audit-extra.sync.ts
index 893d1afb8a0..daa60aed73f 100644
--- a/src/security/audit-extra.sync.ts
+++ b/src/security/audit-extra.sync.ts
@@ -3,6 +3,7 @@ import {
   resolveSandboxConfigForAgent,
   resolveSandboxToolPolicyForAgent,
 } from "../agents/sandbox.js";
+import { isDangerousNetworkMode, normalizeNetworkMode } from "../agents/sandbox/network-mode.js";
 /**
  * Synchronous security audit collector functions.
  *
@@ -830,8 +831,8 @@ export function collectSandboxDangerousConfigFindings(cfg: OpenClawConfig): Secu
     }
 
     const network = typeof docker.network === "string" ? docker.network : undefined;
-    const normalizedNetwork = network?.trim().toLowerCase();
-    if (normalizedNetwork === "host" || normalizedNetwork?.startsWith("container:")) {
+    const normalizedNetwork = normalizeNetworkMode(network);
+    if (isDangerousNetworkMode(network)) {
       const modeLabel = normalizedNetwork === "host" ? '"host"' : `"${network}"`;
       const detail =
         normalizedNetwork === "host"