CVE-2017-11761

Microsoft Exchange Information Disclosure Vulnerability

CVE-2017-11761 is fixed in 4 products on 1 platform, first by KB4045655, released December 12, 2017. It is not reported as exploited. Patch Radar priority: High.

High
CVSS
n/a
Important
Exploitation
None reported
Exploitation Unlikely
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0656
93rd percentile

<p>An input sanitization issue exists with Microsoft Exchange that could potentially result in unintended Information Disclosure. An attacker who successfully exploited the vulnerability could identify the existence of RFC1918 addresses on the local network from a client on the Internet. An attacker could use this internal host information as part of a larger attack.</p> <p>To exploit the vulnerability, an attacker could include specially crafted tags in Calendar-related messages sent to an Exchange server. These specially-tagged messages could prompt the Exchange server to fetch information from internal servers. By observing telemetry from these requests, a client could discern properties of internal hosts intended to be hidden from the Internet.</p> <p>The update corrects the way that Exchange parses Calendar-related messages.</p>

Where it's fixed

ProductFixed inFixReleased
Microsoft
Microsoft Exchange Server 2013 Cumulative Update 17 KB4045655 Dec 12, 2017
Microsoft Exchange Server 2013 Cumulative Update 18 KB4045655 Dec 12, 2017
Microsoft Exchange Server 2016 Cumulative Update 6 KB4045655 Dec 12, 2017
Microsoft Exchange Server 2016 Cumulative Update 7 KB4045655 Dec 12, 2017

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