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 versions from 0.1 to 1.19 are therefore still vulnerable to entity expansions which can lead to a denial of service attack. Users should upgrade to 1.19.1 or later.
The MITRE CVE dictionary describes this issue as:
Find out more about CVE-2018-11796 from the MITRE CVE dictionary dictionary and NIST NVD.
This issue affects the versions of tika which is embedded in the nutch package as shipped with Red Hat Satellite 5. The tika server is not exposed, as such exploitation is difficult, Red Hat Product Security has rated this issue as having security impact of Low. A future update may address this issue. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.
NOTE: The following CVSS v3 metrics and score provided are preliminary and subject to review.
| CVSS3 Base Score | 7.5 |
|---|---|
| CVSS3 Base Metrics | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| Attack Vector | Network |
| Attack Complexity | Low |
| Privileges Required | None |
| User Interaction | None |
| Scope | Unchanged |
| Confidentiality | None |
| Integrity Impact | None |
| Availability Impact | High |
| Platform | Package | State |
|---|---|---|
| Red Hat Software Collections for Red Hat Enterprise Linux | rh-eclipse46-tika | Affected |
| Red Hat Satellite 5 | tika | Will not fix |
| Red Hat JBoss Fuse Service Works 6 | tika-core | Under investigation |
| Red Hat JBoss Fuse 7 | camel-tika | Under investigation |
| Red Hat JBoss Data Virtualization 6 | tika-core | Under investigation |
| Red Hat JBoss BRMS 6 | tika-core | Under investigation |
| Red Hat JBoss BRMS 5 | tika-core | Under investigation |
| Red Hat JBoss BPMS 6 | tika-core | Under investigation |
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