Vulnerability Monitor

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CVE-2017-9233

XML External Entity vulnerability in libexpat 2.2.0 and earlier (Expat XML Parser Library) allows attackers to put the parser in an infinite loop using a malformed external entity definition from an external DTD.

Security Impact Summary

This vulnerability carries a HIGH severity rating with a CVSS v3.1 score of 7.5, indicating it can be exploited remotely over the network with relatively low complexity without requiring user interaction and does not require pre-existing privileges . The vulnerability impacts and availability (service disruption) for affected systems. Impacting 3 products from libexpat_project, from python, from debian organizations running these solutions should prioritize assessment and patching.

Historical Context

First disclosed in 2017, this vulnerability was reported during a period defined by widespread IoT adoption challenges, mobile security concerns, and the emergence of advanced persistent threat (APT) techniques. Contemporary mitigation strategies focused on secure development practices and third-party component vetting.

Published

2017-07-25T20:29:00.220

Last Modified

2025-04-20T01:37:25.860

Status

Deferred

Source

[email protected]

Severity

CVSSv3.1: 7.5 (HIGH)

CVSSv2 Vector

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

Access Vector: NETWORK
Access Complexity: LOW
Authentication: NONE
Confidentiality Impact: NONE
Integrity Impact: NONE
Availability Impact: PARTIAL

Exploitability Score

10.0

Impact Score

2.9

Weaknesses

Type: Primary
CWE-611
CWE-835

Affected Vendors & Products

Type	Vendor	Product	Version/Range	Vulnerable?
Application	libexpat_project	libexpat	≤ 2.2.0	Yes
Application	python	python	< 2.7.15	Yes
Application	python	python	< 3.3.7	Yes
Application	python	python	< 3.4.7	Yes
Application	python	python	< 3.5.4	Yes
Application	python	python	< 3.6.2	Yes
Operating System	debian	debian_linux	8.0	Yes
Operating System	debian	debian_linux	9.0	Yes
Operating System	debian	debian_linux	10.0	Yes

References

http://www.debian.org/security/2017/dsa-3898 Third Party Advisory ([email protected])
http://www.openwall.com/lists/oss-security/2017/06/17/7 Mailing List, VDB Entry ([email protected])
http://www.securityfocus.com/bid/99276 Third Party Advisory, VDB Entry ([email protected])
http://www.securitytracker.com/id/1039427 Third Party Advisory, VDB Entry ([email protected])
https://github.com/libexpat/libexpat/blob/master/expat/Changes Release Notes, Third Party Advisory ([email protected])
https://libexpat.github.io/doc/cve-2017-9233/ Exploit, Technical Description, Vendor Advisory ([email protected])
https://lists.apache.org/thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e33b6e698b9d696b%40%3Cissues.bookkeeper.apache.org%3E ([email protected])
https://lists.apache.org/thread.html/rf4c02775860db415b4955778a131c2795223f61cb8c6a450893651e4%40%3Cissues.bookkeeper.apache.org%3E ([email protected])
https://support.apple.com/HT208112 Third Party Advisory ([email protected])
https://support.apple.com/HT208113 Third Party Advisory ([email protected])
https://support.apple.com/HT208115 Third Party Advisory ([email protected])
https://support.apple.com/HT208144 Third Party Advisory ([email protected])
https://support.f5.com/csp/article/K03244804 Third Party Advisory ([email protected])
http://www.debian.org/security/2017/dsa-3898 Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
http://www.openwall.com/lists/oss-security/2017/06/17/7 Mailing List, VDB Entry (af854a3a-2127-422b-91ae-364da2661108)
http://www.securityfocus.com/bid/99276 Third Party Advisory, VDB Entry (af854a3a-2127-422b-91ae-364da2661108)
http://www.securitytracker.com/id/1039427 Third Party Advisory, VDB Entry (af854a3a-2127-422b-91ae-364da2661108)
https://github.com/libexpat/libexpat/blob/master/expat/Changes Release Notes, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://libexpat.github.io/doc/cve-2017-9233/ Exploit, Technical Description, Vendor Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://lists.apache.org/thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e33b6e698b9d696b%40%3Cissues.bookkeeper.apache.org%3E (af854a3a-2127-422b-91ae-364da2661108)
https://lists.apache.org/thread.html/rf4c02775860db415b4955778a131c2795223f61cb8c6a450893651e4%40%3Cissues.bookkeeper.apache.org%3E (af854a3a-2127-422b-91ae-364da2661108)
https://support.apple.com/HT208112 Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://support.apple.com/HT208113 Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://support.apple.com/HT208115 Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://support.apple.com/HT208144 Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://support.f5.com/csp/article/K03244804 Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)

How SecUtils Interprets This CVE

SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For libexpat_project's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.