{"id":"EUVD-2026-25388","revision":"133af3eaad4b4b5e81a2a81a432d672c","records":[{"revision":"133af3eaad4b4b5e81a2a81a432d672c","observedAt":"2026-11-01T07:06:53.516+00:00","statement":{"source":"euvd","id":"EUVD-2026-25388","aliases":["CVE-2026-41319"],"title":"MailKit is a cross-platform mail client library built on top of MimeKit. A STARTTLS Response Injection vulnerability in versions prior to 4.16.0 allows a Man-in-the-Middle attacker to inject arbitrary protocol responses across the plaintext…","description":"MailKit is a cross-platform mail client library built on top of MimeKit. A STARTTLS Response Injection vulnerability in versions prior to 4.16.0 allows a Man-in-the-Middle attacker to inject arbitrary protocol responses across the plaintext-to-TLS trust boundary, enabling SASL authentication mechanism downgrade (e.g., forcing PLAIN instead of SCRAM-SHA-256). The internal read buffer in `SmtpStream`, `ImapStream`, and `Pop3Stream` is not flushed when the underlying stream is replaced with `SslStream` during STARTTLS upgrade, causing pre-TLS attacker-injected data to be processed as trusted post-TLS responses. Version 4.16.0 patches the issue.","state":0,"publishedAt":null,"modifiedAt":null,"affected":[],"metrics":[{"system":"EUVD CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N","score":6.5,"severity":null}],"references":["https://github.com/jstedfast/MailKit/security/advisories/GHSA-9j88-vvj5-vhgr"],"sourceUrl":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-25388","license":"ENISA EUVD · source terms and attribution apply","enrichment":{"sourceStatus":null,"weaknesses":[],"productCriteria":[],"sourceDates":{"datePublished":"Apr 24, 2026, 3:07:24 AM","dateUpdated":"Apr 25, 2026, 1:46:35 AM"},"relatedAdvisories":[],"note":"EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON."},"key":"euvd:EUVD-2026-25388","identifiers":["EUVD-2026-25388","CVE-2026-41319"]},"retained":false,"historicalAffected":[]}],"coverage":[]}