[CVE-2018-11796] Apache Tika Denial of Service via XML Entity Expansion Vulnerability

[Tim Allison <tallison () apache org>]

CVE-2018-11796: Apache Tika Denial of Service via XML Entity Expansion
Vulnerability

Severity: Medium

Vendor:
The Apache Software Foundation

Versions Affected:
Apache Tika 0.1 to 1.19

Description:
In Apache Tika 1.19 (CVE-2018-11761), we added an entity expansion
limit for XML parsing.  However, Tika reuses SAXParsers and calls
reset() after each parse, which, for Xerces2 parsers, as per the
documentation, removes the user-specified SecurityManager and
thus removes entity expansion limits after the first parse.
Apache Tika 1.19 is therefore still vulnerable to entity
expansions which can lead to a denial of service attack.

Mitigation:
Apache Tika users should upgrade to 1.19.1 or later

Credit:
This issue was discovered by Slava Gorelik of CloudAlly.