{"schemaVersion":3,"id":"CVE-2026-40203","aliases":["ALPINE-CVE-2026-40203","UBUNTU-CVE-2026-40203","DEBIAN-CVE-2026-40203"],"status":"published","duplicateOf":null,"title":null,"description":"When IMAP compression is enabled, the same compression state is reused across responses in a session, so response sizes depend on both attacker-supplied mail and other mail in the same mailbox. An attacker that can send mail to a user and can also observe the sizes of that user's IMAP traffic can confirm whether the body of a small message matches a guessed text. Recovery of arbitrary unknown content was not demonstrated, but the attack can disclose whether a secret-like message body matches a candidate. Disable IMAP compression. Update to non-vulnerable version. 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