Cyber ·
USN-9000-1: denial of service in the Twisted IMAP server
Ubuntu Security advisory on wildcard pattern handling in the Twisted IMAP server, which may allow denial of service through excessive resource use by an authenticated attacker.
Advisory USN-9000-1, published in the Ubuntu Security feed on November 4, 2026, describes a problem in how the Twisted IMAP server handles wildcard patterns in mailbox listing commands. According to the text, a remote authenticated attacker could possibly exploit this flaw to make Twisted consume excessive resources, leading to denial of service. The content is a machine translation of the original advisory, which should be consulted at the official Ubuntu Security source to confirm affected versions and the recommended fix. The available text does not mention active exploitation or the exact number of affected systems. For teams running mail servers based on Twisted, the practical step is to check whether the library is in use and apply the update indicated by the vendor.