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Vulnerability record · CVE-2011-1506 · published 22 March 2011

CVE-2011-1506: Kerio connect improper input validation vulnerability

Kerio · Connect

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.

6.8 CVSS 2.0 Medium EPSS 2.5% · top 16.1% CWE-20 · Improper input validation
6.8CVSS 2.0 base score
2.5%EPSS exploitation probability, 30 days
NoNot in CISA KEV
2Affected product versions listed by NVD
12References
16 Jun 2026Last modified by NVD

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.

AV:N/AC:M/Au:N/C:P/I:P/A:P

Affected products

2 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://secunia.com/advisories/43678 Vendor Advisory
http://www.kb.cert.org/vuls/id/555316 US Government Resource
http://www.kb.cert.org/vuls/id/MAPG-8D9M4P US Government Resource
http://www.securityfocus.com/bid/46767
http://www.vupen.com/english/advisories/2011/0610 Vendor Advisory
https://exchange.xforce.ibmcloud.com/vulnerabilities/65932
http://secunia.com/advisories/43678 Vendor Advisory
http://www.kb.cert.org/vuls/id/555316 US Government Resource
http://www.kb.cert.org/vuls/id/MAPG-8D9M4P US Government Resource
http://www.securityfocus.com/bid/46767
http://www.vupen.com/english/advisories/2011/0610 Vendor Advisory
https://exchange.xforce.ibmcloud.com/vulnerabilities/65932

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

10.0CVE-2008-0860Kerio avg plugin vulnerabilityUnspecified vulnerability in the AVG plugin in Kerio MailServer before 6.5.0 has unspecified impact via unknown remote attack vectors related to null…EPSS 1.5%10.0CVE-2007-3993Kerio mailserver vulnerabilityUnspecified vulnerability in the attachment filter in Kerio MailServer before 6.4.1 has unknown impact and remote attack vectors.EPSS 1.8%10.0CVE-2004-2441Kerio mailserver vulnerabilityUnspecified vulnerability in Kerio MailServer before 6.0.3 has unknown impact and unknown remote attack vectors, related to a "potential security iss…EPSS 1.7%7.8CVE-2006-1158Kerio mailserver vulnerabilityKerio MailServer before 6.1.3 Patch 1 allows remote attackers to cause a denial of service (application crash) via a crafted IMAP LOGIN command.EPSS 2.1%7.5CVE-2008-0858Kerio mailserver code injection vulnerabilityBuffer overflow in the Visnetic anti-virus plugin in Kerio MailServer before 6.5.0 might allow remote attackers to execute arbitrary code via unspeci…EPSS 4.0%7.5CVE-2005-1062Kerio mailserver vulnerabilityThe administration protocol for Kerio WinRoute Firewall 6.x up to 6.0.10, Personal Firewall 4.x up to 4.1.2, and MailServer up to 6.0.8 allows remote…EPSS 2.6%7.5CVE-2003-0487Kerio mailserver vulnerabilityMultiple buffer overflows in Kerio MailServer 5.6.3 allow remote authenticated users to cause a denial of service and possibly execute arbitrary code…EPSS 11%6.8CVE-2002-1434Kerio mailserver vulnerabilityMultiple cross-site scripting (XSS) vulnerabilities in the Web mail module of Kerio MailServer 5.0 allow remote attackers to execute HTML script as o…EPSS 4.3%

Source: NIST National Vulnerability Database (record CVE-2011-1506), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.