diff --git a/clients/js/test/close.test.ts b/clients/js/test/close.test.ts
index 09f3bed..5b636ba 100644
--- a/clients/js/test/close.test.ts
+++ b/clients/js/test/close.test.ts
@@ -4,7 +4,9 @@ import {
     appendTransactionMessageInstructions,
     generateKeyPairSigner,
     getUtf8Encoder,
+    isSolanaError,
     pipe,
+    SOLANA_ERROR__INSTRUCTION_ERROR__INCORRECT_AUTHORITY,
 } from '@solana/kit';
 import test from 'ava';
 import { fetchMaybeMetadata, getCloseInstruction, getSetAuthorityInstruction } from '../src';
@@ -270,3 +272,86 @@ test('it can close keypair buffers', async t => {
     const account = await fetchMaybeMetadata(client.rpc, buffer.address);
     t.false(account.exists);
 });
+
+test('it cannot close a keypair buffer with a different authority set using the buffer keypair', async t => {
+    // Given the following payer.
+    const client = createDefaultSolanaClient();
+    const payer = await generateKeyPairSignerWithSol(client);
+
+    // And the following pre-allocated keypair buffer.
+    const buffer = await createKeypairBuffer(client, {
+        payer,
+        data: getUtf8Encoder().encode('Hello, World!'),
+    });
+
+    // And we set a different authority on the buffer account.
+    const bufferAuthority = await generateKeyPairSigner();
+    const setAuthorityIx = getSetAuthorityInstruction({
+        account: buffer.address,
+        authority: buffer,
+        newAuthority: bufferAuthority.address,
+    });
+    await pipe(
+        await createDefaultTransaction(client, payer),
+        tx => appendTransactionMessageInstruction(setAuthorityIx, tx),
+        tx => signAndSendTransaction(client, tx),
+    );
+
+    // When the buffer keypair tries to close its own account.
+    const closeIx = getCloseInstruction({
+        account: buffer.address,
+        authority: buffer,
+        destination: payer.address,
+    });
+    const promise = pipe(
+        await createDefaultTransaction(client, payer),
+        tx => appendTransactionMessageInstruction(closeIx, tx),
+        tx => signAndSendTransaction(client, tx),
+    );
+
+    // Then we expect a program error.
+    const error = await t.throwsAsync(promise);
+    t.true(isSolanaError(error));
+    t.true(isSolanaError(error.cause, SOLANA_ERROR__INSTRUCTION_ERROR__INCORRECT_AUTHORITY));
+});
+
+test('it can close a keypair buffer with its authority', async t => {
+    // Given the following payer.
+    const client = createDefaultSolanaClient();
+    const payer = await generateKeyPairSignerWithSol(client);
+
+    // And the following pre-allocated keypair buffer.
+    const buffer = await createKeypairBuffer(client, {
+        payer,
+        data: getUtf8Encoder().encode('Hello, World!'),
+    });
+
+    // And we set a different authority on the buffer account.
+    const bufferAuthority = await generateKeyPairSigner();
+    const setAuthorityIx = getSetAuthorityInstruction({
+        account: buffer.address,
+        authority: buffer,
+        newAuthority: bufferAuthority.address,
+    });
+    await pipe(
+        await createDefaultTransaction(client, payer),
+        tx => appendTransactionMessageInstruction(setAuthorityIx, tx),
+        tx => signAndSendTransaction(client, tx),
+    );
+
+    // When the authority closes the buffer account.
+    const closeIx = getCloseInstruction({
+        account: buffer.address,
+        authority: bufferAuthority,
+        destination: payer.address,
+    });
+    await pipe(
+        await createDefaultTransaction(client, payer),
+        tx => appendTransactionMessageInstruction(closeIx, tx),
+        tx => signAndSendTransaction(client, tx),
+    );
+
+    // Then we expect the buffer account to no longer exist.
+    const account = await fetchMaybeMetadata(client.rpc, buffer.address);
+    t.false(account.exists);
+});
diff --git a/program/src/processor/close.rs b/program/src/processor/close.rs
index ebc3678..d8f2ccc 100644
--- a/program/src/processor/close.rs
+++ b/program/src/processor/close.rs
@@ -27,7 +27,7 @@ pub fn close(accounts: &[AccountInfo]) -> ProgramResult {
 
     // account
     // - must have data
-    // - authority must match (if not a keypair buffer)
+    // - authority must match
 
     let account_data = if account.data_is_empty() {
         return Err(ProgramError::UninitializedAccount);
@@ -35,20 +35,16 @@ pub fn close(accounts: &[AccountInfo]) -> ProgramResult {
         unsafe { account.borrow_data_unchecked() }
     };
 
-    // We only need to validate the authority if it is not a keypair buffer,
-    // since we already validated that the authority is a signer.
-    if account.key() != authority.key() {
-        match AccountDiscriminator::try_from(account_data[0])? {
-            AccountDiscriminator::Buffer => {
-                let buffer = unsafe { Buffer::from_bytes_unchecked(account_data) };
-                validate_authority(buffer, authority, program, program_data)?
-            }
-            AccountDiscriminator::Metadata => {
-                let header = validate_metadata(account)?;
-                validate_authority(header, authority, program, program_data)?
-            }
-            _ => return Err(ProgramError::InvalidAccountData),
+    match AccountDiscriminator::try_from(account_data[0])? {
+        AccountDiscriminator::Buffer => {
+            let buffer = unsafe { Buffer::from_bytes_unchecked(account_data) };
+            validate_authority(buffer, authority, program, program_data)?
         }
+        AccountDiscriminator::Metadata => {
+            let header = validate_metadata(account)?;
+            validate_authority(header, authority, program, program_data)?
+        }
+        _ => return Err(ProgramError::InvalidAccountData),
     }
 
     // Move the lamports to the destination account and close the account.