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CVE-2017-9233

29
FAUCET Score

CVE-2017-9233 is an XML External Entity (XXE) vulnerability in libexpat 2.2.0 and earlier, affecting various Debian and Python products that utilize the library. This flaw allows attackers to trigger an infinite loop in the XML parser by crafting a malformed external entity definition within an external DTD. With a CVSS score of 7.5 (High), the vulnerability presents a network-based attack vector with low complexity, leading to high availability impact (denial of service) without requiring user interaction or privileges. There is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
<= 2.2.0CPE matchmatch criteria
cpe:2.3:a:libexpat_project:libexpat:*:*:*:*:*:*:*:*
>= 2.7.0, < 2.7.15CPE matchmatch criteria
cpe:2.3:a:python:python:*:*:*:*:*:*:*:*
>= 3.3.0, < 3.3.7CPE matchmatch criteria
cpe:2.3:a:python:python:*:*:*:*:*:*:*:*
>= 3.4.0, < 3.4.7CPE matchmatch criteria
cpe:2.3:a:python:python:*:*:*:*:*:*:*:*
>= 3.5.0, < 3.5.4CPE matchmatch criteria
cpe:2.3:a:python:python:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

CVSS:3.1/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 Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
9.05%
Probability of exploitation in next 30 days
EPSS Percentile
94.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-25
Model: v2026.06.15
This CVE's current EPSS score of 0.0905 is in the 91st percentile among its peer group of 51,485 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Vendor Patches (16)

redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 5Fixed in: expat
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 5Fixed in: firefox
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 5Fixed in: thunderbird
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 5Fixed in: xmlrpc-c
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 5Fixed in: xulrunner
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: compat-expat1
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: firefox
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: thunderbird
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: xulrunner
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: expat
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: firefox
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: thunderbird
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: xulrunner
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Virtualization 3Fixed in: mingw-virt-viewer
redhatend of lifevia redhat_api
Product: Red Hat JBoss Enterprise Application Platform 6Fixed in: httpd
redhatend of lifevia redhat_api
Product: Red Hat JBoss Enterprise Web Server 2Fixed in: httpd

Vendor Advisories (1)

redhatCVE-2017-9233Moderate

expat: Inifinite loop due to invalid XML in external entity

Jun 14, 2017

References

github.com / libexpat/libexpat/blob/master/expat/Changes
Release NotesThird Party Advisory
libexpat.github.io / doc/cve-2017-9233
ExploitTechnical DescriptionVendor Advisory
lists.apache.org / thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e33b6e698b9d696b%40%3Cissues.bookkeeper.apache.org%3E
lists.apache.org / thread.html/rf4c02775860db415b4955778a131c2795223f61cb8c6a450893651e4%40%3Cissues.bookkeeper.apache.org%3E
support.apple.com / HT208112
Third Party Advisory
support.apple.com / HT208113
Third Party Advisory
support.apple.com / HT208115
Third Party Advisory
support.apple.com / HT208144
Third Party Advisory
support.f5.com / csp/article/K03244804
Third Party Advisory
debian.org / security/2017/dsa-3898
Third Party Advisory
openwall.com / lists/oss-security/2017/06/17/7
Mailing ListVDB Entry
securityfocus.com / bid/99276
Third Party AdvisoryVDB Entry
securitytracker.com / id/1039427
Third Party AdvisoryVDB Entry