CVE-2011-1506
CWE-20Published: March 22, 2011· Updated: Jun 16, 2026
Official Description
The STARTTLS implementation in Kerio Connect 7.1.4 build 2985 and MailServer 6.x 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. NOTE: some of these details are obtained from third party information.
Technical Analysis
CVE-2011-1506 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
CVSS v3.1 Vector Breakdown
Affected Vendors & Products
Exploit & PoC Resources
Official Patches & Advisories
All References (12)
Quick Facts
Related CVEs (CWE-20)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2011-1506 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts