diff --git a/src/app/(app)/admin/users/actions-security.test.ts b/src/app/(app)/admin/users/actions-security.test.ts
new file mode 100644
index 00000000..54001d4b
--- /dev/null
+++ b/src/app/(app)/admin/users/actions-security.test.ts
@@ -0,0 +1,160 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+
+// Hoist mocks so they can be used in vi.mock factories
+const {
+  mockGetUser,
+  mockFindFirstUserProfiles,
+  mockFindFirstAuthUsers,
+  mockFindFirstInvitedUsers,
+  mockInsertInvitedUsers,
+  mockUpdateInvitedUsers,
+  mockSendInviteEmail,
+  mockRequireSiteUrl,
+  mockRevalidatePath
+} = vi.hoisted(() => ({
+  mockGetUser: vi.fn(),
+  mockFindFirstUserProfiles: vi.fn(),
+  mockFindFirstAuthUsers: vi.fn(),
+  mockFindFirstInvitedUsers: vi.fn(),
+  mockInsertInvitedUsers: vi.fn(),
+  mockUpdateInvitedUsers: vi.fn(),
+  mockSendInviteEmail: vi.fn(),
+  mockRequireSiteUrl: vi.fn(),
+  mockRevalidatePath: vi.fn(),
+}));
+
+// Mock dependencies
+vi.mock("next/cache", () => ({
+  revalidatePath: mockRevalidatePath,
+}));
+
+vi.mock("~/lib/logger", () => ({
+  log: {
+    error: vi.fn(),
+    info: vi.fn(),
+    warn: vi.fn(),
+  },
+}));
+
+vi.mock("~/lib/url", () => ({
+  requireSiteUrl: mockRequireSiteUrl,
+}));
+
+vi.mock("~/lib/email/invite", () => ({
+  sendInviteEmail: mockSendInviteEmail,
+}));
+
+// Mock Supabase
+vi.mock("~/lib/supabase/server", () => ({
+  createClient: vi.fn().mockResolvedValue({
+    auth: {
+      getUser: mockGetUser,
+    },
+  }),
+}));
+
+// Mock Drizzle
+vi.mock("~/server/db", () => ({
+  db: {
+    query: {
+      userProfiles: {
+        findFirst: mockFindFirstUserProfiles,
+      },
+      authUsers: {
+        findFirst: mockFindFirstAuthUsers,
+      },
+      invitedUsers: {
+        findFirst: mockFindFirstInvitedUsers,
+      },
+    },
+    insert: () => ({
+      values: () => ({
+        returning: mockInsertInvitedUsers,
+      }),
+    }),
+    update: () => ({
+      set: () => ({
+        where: mockUpdateInvitedUsers,
+      }),
+    }),
+  },
+}));
+
+// Import actions after mocks are set up
+import { inviteUser, resendInvite } from "./actions";
+
+describe("Admin User Actions Security - Error Handling", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+
+    // Default mocks for success path
+    mockGetUser.mockResolvedValue({
+      data: { user: { id: "admin-id" } }
+    });
+
+    // User is admin
+    mockFindFirstUserProfiles.mockResolvedValue({
+      role: "admin",
+      name: "Admin User"
+    });
+
+    // User to invite doesn't exist
+    mockFindFirstAuthUsers.mockResolvedValue(null);
+    mockFindFirstInvitedUsers.mockResolvedValue(null);
+
+    // Insert success
+    mockInsertInvitedUsers.mockResolvedValue([{ id: "new-user-id" }]);
+
+    // Site URL
+    mockRequireSiteUrl.mockReturnValue("http://localhost:3000");
+  });
+
+  it("inviteUser should not leak email provider errors", async () => {
+    // Simulate email failure with sensitive info
+    mockSendInviteEmail.mockResolvedValue({
+      success: false,
+      error: "Connection refused to 192.168.1.55:25",
+    });
+
+    const formData = new FormData();
+    formData.append("firstName", "Test");
+    formData.append("lastName", "User");
+    formData.append("email", "test@example.com");
+    formData.append("role", "member");
+    formData.append("sendInvite", "true");
+
+    // We expect it to fail, but we need to check the message
+    await expect(inviteUser(formData)).rejects.toThrow();
+
+    try {
+      await inviteUser(formData);
+    } catch (error: any) {
+      expect(error.message).not.toContain("192.168.1.55");
+      expect(error.message).toBe("Failed to send invitation email");
+    }
+  });
+
+  it("resendInvite should not leak email provider errors", async () => {
+    // Setup existing invited user
+    mockFindFirstInvitedUsers.mockResolvedValue({
+      id: "invited-id",
+      email: "test@example.com",
+      firstName: "Test",
+    });
+
+    // Simulate email failure with sensitive info
+    mockSendInviteEmail.mockResolvedValue({
+      success: false,
+      error: "Invalid API Key: sk_live_12345",
+    });
+
+    await expect(resendInvite("invited-id")).rejects.toThrow();
+
+    try {
+      await resendInvite("invited-id");
+    } catch (error: any) {
+      expect(error.message).not.toContain("sk_live_12345");
+      expect(error.message).toBe("Failed to send invitation email");
+    }
+  });
+});
diff --git a/src/app/(app)/admin/users/actions.ts b/src/app/(app)/admin/users/actions.ts
index cbb2f8b4..1bf38fac 100644
--- a/src/app/(app)/admin/users/actions.ts
+++ b/src/app/(app)/admin/users/actions.ts
@@ -7,6 +7,7 @@ import { eq } from "drizzle-orm";
 import { revalidatePath } from "next/cache";
 import { sendInviteEmail } from "~/lib/email/invite";
 import { requireSiteUrl } from "~/lib/url";
+import { log } from "~/lib/logger";
 import { inviteUserSchema, updateUserRoleSchema } from "./schema";
 
 async function verifyAdmin(userId: string): Promise<void> {
@@ -135,9 +136,11 @@ export async function inviteUser(
     });
 
     if (!emailResult.success) {
-      throw new Error(
-        `Failed to send invitation email: ${String(emailResult.error)}`
+      log.error(
+        { error: emailResult.error, email: validated.email },
+        "Failed to send invitation email"
       );
+      throw new Error("Failed to send invitation email");
     }
 
     await db
@@ -185,9 +188,11 @@ export async function resendInvite(userId: string): Promise<{ ok: boolean }> {
   });
 
   if (!emailResult.success) {
-    throw new Error(
-      `Failed to send invitation email: ${String(emailResult.error)}`
+    log.error(
+      { error: emailResult.error, userId },
+      "Failed to send invitation email"
     );
+    throw new Error("Failed to send invitation email");
   }
 
   await db