CVE-2014-3556
The STARTTLS implementation in mail/ngx_mail_smtp_handler.c in the SMTP proxy in nginx 1.5.x and...
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.
Exploit likelihood
What each source reports
NVD Score used
6.8
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.
- Record
CVE-2014-3556- CVSS 2.0
- 6.8 Medium
AV:N/AC:M/Au:N/C:P/I:P/A:P - Weakness
- CWE-77
- Updated
- 2026-11-02
CVE List No score
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.
- Record
CVE-2014-3556- Updated
- 2026-11-02
EUVDEUVD-2014-3539 No score
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.
- Record
EUVD-2014-3539- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-8277-2g6w-24gq No score
The STARTTLS implementation in mail/ngx_mail_smtp_handler.c in the SMTP proxy in nginx 1.5.x and...
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.
- Record
GHSA-8277-2g6w-24gq- Weakness
- CWE-77
- Updated
- 2026-11-02
OSV No score
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.
- Record
CVE-2014-3556- Updated
- 2026-11-02
OSVDEBIAN-CVE-2014-3556 No score
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.
- Record
DEBIAN-CVE-2014-3556- Updated
- 2026-11-02
OSVopenSUSE-SU-2024:10044-1 No score
nginx-1.11.4-2.5 on GA media
These are all security issues fixed in the nginx-1.11.4-2.5 package on the GA media of openSUSE Tumbleweed.
- Record
openSUSE-SU-2024:10044-1- Updated
- 2026-11-02
OSVUBUNTU-CVE-2014-3556 No score
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.
- Record
UBUNTU-CVE-2014-3556- Updated
- 2026-11-02
Affected products
Affected packages
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | ||
| affected | ||
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2014-3556 is a medium vulnerability (CVSS 6.8) in F5 Nginx, published December 29, 2014. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 7.83%, the 94th percentile. Fixed in nginx 1.6.1-1.
References
marc.info?l=bugtraq&m=142103967620673&w=2
bugzilla.redhat.com/show_bug.cgi?id=1126891
mailman.nginx.org/pipermail/nginx-announce/2014/000144.html
nginx.org/download/patch.2014.starttls.txt
nvd.nist.gov/vuln/detail/CVE-2014-3556
github.com/advisories/GHSA-8277-2g6w-24gq
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security-tracker.debian.org/tracker/CVE-2014-3556
ubuntu.com/security/CVE-2014-3556
cve.org/CVERecord?id=CVE-2014-3556
suse.com/security/cve/CVE-2011-4315
suse.com/security/cve/CVE-2012-2089
suse.com/security/cve/CVE-2013-2070
suse.com/security/cve/CVE-2013-4547
suse.com/security/cve/CVE-2014-0133
suse.com/security/cve/CVE-2014-3556
suse.com/security/cve/CVE-2014-3616
suse.com/security/cve/CVE-2016-0742
suse.com/security/cve/CVE-2016-0746
suse.com/security/cve/CVE-2016-0747
suse.com/security/cve/CVE-2016-4450