diff --git a/ui/auth.config.test.ts b/ui/auth.config.test.ts
new file mode 100644
index 0000000000..6df8d14dfe
--- /dev/null
+++ b/ui/auth.config.test.ts
@@ -0,0 +1,183 @@
+import { beforeEach, describe, expect, it, vi } from "vitest";
+
+import { authConfig } from "./auth.config";
+import type { RolePermissionAttributes } from "./types/users";
+
+const { getUserByMeMock } = vi.hoisted(() => ({
+  getUserByMeMock: vi.fn(),
+}));
+
+vi.mock("next-auth", () => ({
+  default: vi.fn(() => ({
+    signIn: vi.fn(),
+    signOut: vi.fn(),
+    auth: vi.fn(),
+    handlers: {},
+  })),
+}));
+
+vi.mock("next-auth/providers/credentials", () => ({
+  default: vi.fn((config) => config),
+}));
+
+vi.mock("./actions/auth", () => ({
+  getToken: vi.fn(),
+  getUserByMe: getUserByMeMock,
+}));
+
+vi.mock("./lib", () => ({
+  apiBaseUrl: "https://api.example.com/api/v1",
+}));
+
+const RESTRICTED_PERMISSIONS: RolePermissionAttributes = {
+  manage_users: false,
+  manage_account: false,
+  manage_providers: false,
+  manage_scans: false,
+  manage_integrations: false,
+  manage_alerts: false,
+  unlimited_visibility: false,
+};
+
+const ELEVATED_PERMISSIONS: RolePermissionAttributes = {
+  ...RESTRICTED_PERMISSIONS,
+  manage_users: true,
+  manage_scans: true,
+};
+
+describe("authConfig JWT callback", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it("should load elevated tenant permissions after switching from a restricted tenant", async () => {
+    // Given
+    const accessToken =
+      "header.eyJzdWIiOiJ1c2VyLTEiLCJ0ZW5hbnRfaWQiOiJ0ZW5hbnQtMiJ9.signature";
+    getUserByMeMock.mockResolvedValue({
+      name: "Tenant User",
+      email: "tenant@example.com",
+      company: "Tenant Company",
+      dateJoined: "2026-01-01",
+      permissions: ELEVATED_PERMISSIONS,
+    });
+    const jwtCallback = authConfig.callbacks?.jwt;
+    if (!jwtCallback) throw new Error("JWT callback is not configured");
+
+    // When
+    const result = await jwtCallback({
+      token: {
+        accessToken: "restricted-access-token",
+        refreshToken: "restricted-refresh-token",
+        tenant_id: "tenant-1",
+        user: {
+          name: "Tenant User",
+          permissions: RESTRICTED_PERMISSIONS,
+        },
+      },
+      user: {} as Parameters<typeof jwtCallback>[0]["user"],
+      trigger: "update",
+      session: {
+        accessToken,
+        refreshToken: "elevated-refresh-token",
+        user: { permissions: RESTRICTED_PERMISSIONS },
+      },
+    });
+
+    // Then
+    expect(getUserByMeMock).toHaveBeenCalledWith(accessToken);
+    expect(result.user).toEqual({
+      name: "Tenant User",
+      email: "tenant@example.com",
+      companyName: "Tenant Company",
+      dateJoined: "2026-01-01",
+      permissions: ELEVATED_PERMISSIONS,
+    });
+  });
+
+  it("should load restricted tenant permissions after switching from an elevated tenant", async () => {
+    // Given
+    const accessToken =
+      "header.eyJzdWIiOiJ1c2VyLTEiLCJ0ZW5hbnRfaWQiOiJ0ZW5hbnQtMSJ9.signature";
+    getUserByMeMock.mockResolvedValue({
+      name: "Tenant User",
+      email: "tenant@example.com",
+      company: "Tenant Company",
+      dateJoined: "2026-01-01",
+      permissions: RESTRICTED_PERMISSIONS,
+    });
+    const jwtCallback = authConfig.callbacks?.jwt;
+    if (!jwtCallback) throw new Error("JWT callback is not configured");
+
+    // When
+    const result = await jwtCallback({
+      token: {
+        accessToken: "elevated-access-token",
+        refreshToken: "elevated-refresh-token",
+        tenant_id: "tenant-2",
+        user: {
+          name: "Tenant User",
+          permissions: ELEVATED_PERMISSIONS,
+        },
+      },
+      user: {} as Parameters<typeof jwtCallback>[0]["user"],
+      trigger: "update",
+      session: {
+        accessToken,
+        refreshToken: "restricted-refresh-token",
+        user: { permissions: ELEVATED_PERMISSIONS },
+      },
+    });
+
+    // Then
+    expect(getUserByMeMock).toHaveBeenCalledWith(accessToken);
+    expect(result.accessToken).toBe(accessToken);
+    expect(result.refreshToken).toBe("restricted-refresh-token");
+    expect(result.tenant_id).toBe("tenant-1");
+    expect(result.user).toMatchObject({
+      permissions: RESTRICTED_PERMISSIONS,
+    });
+  });
+
+  it("should preserve the current session when the switched tenant user cannot be loaded", async () => {
+    // Given
+    vi.spyOn(console, "warn").mockImplementation(() => undefined);
+    getUserByMeMock.mockRejectedValue(new Error("Temporary API failure"));
+    const jwtCallback = authConfig.callbacks?.jwt;
+    if (!jwtCallback) throw new Error("JWT callback is not configured");
+    const currentToken = {
+      accessToken: "current-access-token",
+      refreshToken: "current-refresh-token",
+      tenant_id: "tenant-1",
+      user: {
+        name: "Tenant User",
+        permissions: RESTRICTED_PERMISSIONS,
+      },
+    };
+
+    // When
+    const result = await jwtCallback({
+      token: currentToken,
+      user: {} as Parameters<typeof jwtCallback>[0]["user"],
+      trigger: "update",
+      session: {
+        accessToken:
+          "header.eyJzdWIiOiJ1c2VyLTEiLCJ0ZW5hbnRfaWQiOiJ0ZW5hbnQtMiJ9.signature",
+        refreshToken: "switched-refresh-token",
+        user: { permissions: ELEVATED_PERMISSIONS },
+      },
+    });
+
+    // Then
+    expect(result).toBe(currentToken);
+    expect(result).toMatchObject({
+      accessToken: "current-access-token",
+      refreshToken: "current-refresh-token",
+      tenant_id: "tenant-1",
+      user: {
+        permissions: RESTRICTED_PERMISSIONS,
+      },
+    });
+    expect(result.error).not.toBe("RefreshAccessTokenError");
+  });
+});
diff --git a/ui/auth.config.ts b/ui/auth.config.ts
index 27f7eb2767..3d5e5f58bc 100644
--- a/ui/auth.config.ts
+++ b/ui/auth.config.ts
@@ -313,10 +313,26 @@ export const authConfig = {
 
       // Handle tenant switch: update tokens from client-side useSession().update()
       if (trigger === "update" && session?.accessToken) {
-        authToken.accessToken = session.accessToken;
-        authToken.refreshToken = session.refreshToken;
-        applyDecodedClaims(authToken, authToken.accessToken, "tenant switch");
-        return authToken;
+        const newAccessToken = session.accessToken;
+
+        try {
+          const userMeResponse = await getUserByMe(newAccessToken);
+          const nextAuthToken: AuthToken = {
+            ...authToken,
+            accessToken: newAccessToken,
+            refreshToken: session.refreshToken,
+            user: tokenUserFromApi(userMeResponse),
+            error: undefined,
+          };
+
+          applyDecodedClaims(nextAuthToken, newAccessToken, "tenant switch");
+
+          return nextAuthToken;
+        } catch (error) {
+          // eslint-disable-next-line no-console
+          console.warn("Error refreshing user after tenant switch:", error);
+          return authToken;
+        }
       }
 
       applyDecodedClaims(authToken, authToken.accessToken);
diff --git a/ui/changelog.d/tenant-switch-permissions.fixed.md b/ui/changelog.d/tenant-switch-permissions.fixed.md
new file mode 100644
index 0000000000..b268fad2dd
--- /dev/null
+++ b/ui/changelog.d/tenant-switch-permissions.fixed.md
@@ -0,0 +1 @@
+Tenant switches now refresh session user permissions for the selected tenant