CVE-2026-41319

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...

CVE-2026-41319

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...

CVE-2026-41319 MailKit has STARTTLS Response Injection via unflushed stream buffer that enables SASL mechanism downgrade

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...

CVE-2026-41319 MailKit has STARTTLS Response Injection via unflushed stream buffer that enables SASL mechanism downgrade

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...

CVE-2026-41319

Summary (CVE-2026-41319) MailKit (MimeKit-based) exposes a STARTTLS vulnerability where the internal read buffers of SmtpStream, ImapStream, and Pop3Stream are not flushed when upgrading to TLS with SslStream. This allows pre-TLS attacker-injected data to be treated as post-TLS, enabling a MITM-b...

CVE-2026-41319

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...

MailKit 注入漏洞

MailKit is a cross-platform email client library developed by Jeffrey Stedfast. Versions of MailKit prior to 4.16.0 had an injection vulnerability. This vulnerability stemmed from STARTTLS response injection, which allowed man-in-the-middle attackers to inject arbitrary protocol responses, thereb...

GHSA-9J88-VVJ5-VHGR MailKit has STARTTLS Response Injection via unflushed stream buffer that enables SASL mechanism downgrade

Summary A STARTTLS Response Injection vulnerability in MailKit 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...

Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

Overview Affected versions of this package are vulnerable to Improper Neutralization of Special Elements in Output Used by a Downstream Component 'Injection' via the internal stream buffers SmtpStream, ImapStream, and Pop3Stream not being flushed during the STARTTLS upgrade process. An attacker c...

PT-2026-34845

Name of the Vulnerable Software and Affected Versions MailKit versions prior to 4.16.0 Description A STARTTLS Response Injection issue allows a Man-in-the-Middle attacker to inject arbitrary protocol responses across the plaintext-to-TLS trust boundary. This can enable a SASL authentication...

CVE-2026-41319

creationtimestamp| type| source ---|---|--- 2026-04-17 21:22:57+00:00| published-proof-of-concept| https://github.com/jstedfast/MailKit/security/advisories/GHSA-9j88-vvj5-vhgr...