VULNERABILITY INTELLIGENCE

CVE-2014-3556

CVSS score6.8 MEDIUM
EPSS probability7.83%
CISA KEVNot currently listed
Published2014-12-29
Last modified2026-06-17
CVSS vectorAV:N/AC:M/Au:N/C:P/I:P/A:P

Description

The STARTTLS implementation in mail/ngx_mail_smtp_handler.c in the SMTP proxy in nginx 1.5.x and 1.6.x before 1.6.1 and 1.7.x before 1.7.4 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 processed after TLS is in place, related to a "plaintext command injection" attack, a similar issue to CVE-2011-0411.

Weakness classification

  • CWE-77: Improper Neutralization of Special Elements used in a Command ('Command Injection')

Primary references