EUVD-2026-28924

Net::IMAP implements Internet Message Access Protocol IMAP client functionality in Ruby. Prior to versions 0.3.10, 0.4.24, 0.5.14, and 0.6.4, a man-in-the-middle attacker can cause Net::IMAPstarttls to return "successfully", without starting TLS. This issue has been patched in versions 0.3.10,...

CVE-2026-42246

Net::IMAP (Ruby) versions before 0.3.10, 0.4.24, 0.5.14, and 0.6.4 are affected by a STARTTLS stripping issue. A man-in-the-middle attacker can cause Net::IMAP#starttls to report a successful TLS upgrade without actually enabling TLS, leaving the socket unencrypted. The vulnerability is mitigated...

PYSEC-2026-24

Apache Airflow's SMTP provider SmtpHook called Python's smtplib.SMTP.starttls without an SSL context, so no certificate validation was performed on the TLS upgrade. A man-in-the-middle between the Airflow worker and the SMTP server could present a self-signed certificate, complete the STARTTLS...

SUSE CVE-2011-0411

The STARTTLS implementation in Postfix 2.4.x before 2.4.16, 2.5.x before 2.5.12, 2.6.x before 2.6.9, and 2.7.x before 2.7.3 does not properly restrict I/O buffering, which allows man-in-the-middle attackers to insert commands into encrypted SMTP sessions by sending a cleartext command that is...

ruby: StartTLS stripping vulnerability in Net::IMAP

Ruby's Net::IMAP module did not raise an exception when receiving an unexpected response to the STARTTLS command and the connection was not upgraded to use TLS. A man-in-the-middle attacker could use this flaw to prevent Ruby applications using Net::IMAP to enable TLS encryption for a connection ...

ruby: StartTLS stripping vulnerability in Net::IMAP

Ruby's Net::IMAP module did not raise an exception when receiving an unexpected response to the STARTTLS command and the connection was not upgraded to use TLS. A man-in-the-middle attacker could use this flaw to prevent Ruby applications using Net::IMAP to enable TLS encryption for a connection ...

pureftpd -- multiple vulnerabilities

Pure-FTPd development team reports: Support for braces expansion in directory listings has been disabled -- Cf. CVE-2011-0418. Fix a STARTTLS flaw similar to Postfix's CVE-2011-0411. If you're using TLS, upgrading is recommended...