CVE-2026-115774 is a denial of service vulnerability in the Twisted IMAP4 server affecting versions 26.4.0 and earlier. An authenticated client can send a SEARCH command with a negative literal size, causing an infinite loop in the parser. This freezes the single-threaded reactor, halting all IMAP connections and any other services running in the same process until it is restarted. There is no impact on confidentiality or integrity, and no code execution is possible.