There have been cases where vulnerability information became public or actual worms were circulating prior to the next scheduled Patch Tuesday. This policy is adequate when the vulnerability is not widely known or is extremely obscure, but that is not always the case. Īn obvious security implication is that security problems that have a solution are withheld from the public for up to a month. This is done to maximize the amount of time available before the upcoming weekend to correct any issues that might arise with those patches, while leaving Monday free to address other unexpected issues that might have arisen over the preceding weekend. Tuesday was chosen as the optimal day of the week to distribute software patches. The following day, informally known as "Exploit Wednesday", marks the time when exploits may appear in the wild which take advantage on unpatched machines of the newly announced vulnerabilities. This system accumulates security patches over a month, and dispatches them all on the second Tuesday of each month, an event for which system administrators may prepare. Microsoft introduced "Patch Tuesday" in October 2003 to reduce the cost of distributing patches.