Definition
An approval exploit is an incident in which a token allowance, operator permission, or related signed authorization is used harmfully. The permission may have been obtained through deception, granted too broadly, or given to a contract that later becomes compromised. The phrase does not necessarily mean the token standard itself is defective: a technically valid authorization can still have an effect the user never intended.
How It Works
A decentralized application may require spending rights to complete a swap or deposit. If those rights are unlimited or remain active, an unsafe spender may be able to transfer additional balances of the affected token. NFT operator permissions and permit-based systems have their own scope and rules. Merely connecting a wallet is different from granting these rights, and deleting the website connection normally does not remove an on-chain allowance.
Key Considerations
Inspect the spender, asset, amount, expiration, and requested action before signing. Limit permissions to the intended use where supported and review permissions that are no longer needed. If an approval is unsafe, use trusted tools to revoke it and verify confirmation, while recognizing that already transferred assets are not restored by revocation. A pending revocation may be overtaken by another transaction. If signing keys were exposed, the problem is broader than an allowance: the holder needs a recovery plan that addresses the compromised credentials, not only a permissions cleanup.