{"id":"AZL-98274","summary":"CVE-2026-40203 affecting package dovecot 2.3.20-1","details":"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. No publicly available exploits are known.","modified":"2026-09-04T05:25:34Z","published":"2026-08-28T12:16:28Z","upstream":["CVE-2026-40203"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-40203"}],"affected":[{"package":{"name":"dovecot","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/dovecot"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"2.3.20-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-98274.json"}}],"schema_version":"1.9.0"}