“The development community is proposing a soft fork, (with NO ROLLBACK; no transactions or blocks will be “reversed”) which will make any transactions that make any calls/callcodes/delegatecalls that execute code with code hash (ie. The DAO and children) lead to the transaction (not just the call, the transaction) being invalid, preventing the Ether from being withdrawn by the attacker past the 27-day window. This will later be followed up by a hard fork which will give token holders the ability to recover their Ether.”
Vitalik Buterin in response to the DAO Vulnerability on June 17