CVE-2009-2636: Cross-site scripting (XSS) vulnerability in the Integration page in the WebMail component in Kerio MailServer

Routine

MEDIUM 4.3DOWNGRADE

CVE-2009-2636 is a medium-severity flaw (CVSS 4.3) affecting kerio mailserver. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Cross-site scripting (XSS) vulnerability in the Integration page in the WebMail component in Kerio MailServer 6.6.0, 6.6.1, 6.6.2, and 6.7.0 allows remote attackers to inject arbitrary web script or HTML via an e-mail message.

Why this priority

No elevated risk signals yet

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	4.3 (Medium)
EPSS exploit chance	1.1% (top 35%)
CISA exploited list	No
Weakness	CWE-79
Published	2009-07-28
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: kerio

Last updated 2026-06-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2009-07-28 19:30 UTCPublished CVE record published
2026-06-16 23:09 UTCUpdated Record last modified

kerio kerio mailserver DOWNGRADE

Affected: 6.6.0 · 6.6.1 · 6.6.2 · 6.7.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 6.6.0

1. Check installed version

apt-cache policy kerio-mailserver || rpm -q kerio-mailserver || kerio-mailserver --version

2. No fixed release: DOWNGRADE to a release before 6.6.0 (Debian / Ubuntu)

apt-cache madison kerio-mailserver sudo apt install kerio-mailserver=<VERSION_BEFORE_6.6.0> sudo apt-mark hold kerio-mailserver

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list kerio-mailserver sudo dnf downgrade kerio-mailserver-<VERSION_BEFORE_6.6.0> sudo dnf versionlock add kerio-mailserver

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2009-2636?

kerio mailserver: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2009-2636 being exploited?

CVE-2009-2636 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2009-2636 affect?

CVE-2009-2636 affects kerio mailserver. Severity is medium (CVSS 4.3). Cross-site scripting (XSS) vulnerability in the Integration page in the WebMail component in Kerio MailServer 6.6.0, 6.6.1, 6.6.2, and 6.7.0 allows remote attackers to inject arbitrary web script or HTML via an e-mail message.

How urgent is CVE-2009-2636?

Priority 31/100. No elevated risk signals yet.

Related CVEs

CVE-2011-1506 MEDIUM 6.8 DOWNGRADE DOWNGRADE The STARTTLS implementation in Kerio Connect 7.1.4 build 2985 and MailServer 6.x does not properly restrict I/
CVE-2008-5769 MEDIUM 4.3 UPGRADE Multiple cross-site scripting (XSS) vulnerabilities in Kerio MailServer before 6.6.2 allow remote attackers to
CVE-2008-5760 MEDIUM 4.3 UPGRADE Cross-site scripting (XSS) vulnerability in error413.php in Kerio MailServer before 6.6.2 allows remote attack
CVE-2008-0860 HIGH 10.0 MITIGATE UPGRADE Unspecified vulnerability in the AVG plugin in Kerio MailServer before 6.5.0 has unspecified impact via unknow
CVE-2008-0859 MEDIUM 5.0 DOWNGRADE Unspecified vulnerability in Kerio MailServer before 6.5.0 allows remote attackers to cause a denial of servic

References

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