UBUNTU-CVE-2026-8286

A vulnerability exists where a new transfer that uses STARTTLS to upgrade the connection might reuse an existing live connection even though the TLS configuration mismatches so it should not...

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...

curl: Server responses received before STARTTLS processed after TLS handshake

A flaw was found in curl. The flaw lies in how curl handles cached or pipelined responses that it receives from either a IMAP, POP3, SMTP or FTP server before the TLS upgrade using STARTTLS. In such a scenario curl even after upgrading to TLS would trust these cached responses treating them as...