Libexpat
CVE-2017-9233
HIGH
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A02:2025 - Security Misconfiguration
ASVS 5.0
V13 - Configuration XML external entity prevention
MITRE ATT&CK
2 techniques across 2 tactics: Initial Access, Collection The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS score of 7.5 (HIGH). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required. Public proof-of-concept exploit code is available. EPSS exploitation probability: 0.25%. |
| Exploit ScenarioDerived | A remote attacker could read arbitrary files or perform SSRF through XML processing by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability. |
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Alert meAnalysisAI
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. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
RemediationAI
No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Disable external entity processing in XML parsers, use JSON instead of XML where possible.
Affects your stack
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Technical ContextAI · show details
This vulnerability is classified as XML External Entity (XXE) (CWE-611), which allows attackers to read arbitrary files or perform SSRF through XML processing. 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. Affected products include: Libexpat Project Libexpat, Python, Debian Debian Linux.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionNVD
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.
Threat Intelligence Overview
NVD
CVE.org
EPSS
GitHub
VulDB
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
XML External Entity (XXE) attacks exploit XML parsers that process Document Type Definitions (DTDs) without proper restrictions.
Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.
Affected Products (CPE)NVD
In Expat (aka libexpat) before 2.4.5, there is an integer overflow in storeRawNames. Rated critical severity (CVSS 9.8),
libexpat in Expat before 2.7.2 allows attackers to trigger large dynamic memory allocations via a small document that is
In libexpat before 2.2.8, crafted XML input could fool the parser into changing from DTD parsing to document parsing too
Malformed UTF-16 decoding in libexpat through 2.8.4 lets remote attackers hide XML markup from the parser: a lone high s
CPU exhaustion in libexpat through 2.9.0 lets remote attackers stall XML parsing workloads by supplying a moderately siz
In libexpat through 2.4.9, there is a use-after free caused by overeager destruction of a shared DTD in XML_ExternalEnti
Alpine Linux: expat fixed in 2.6.2-r0
Denial of service in libexpat before 2.8.1 lets remote attackers exhaust CPU by submitting moderately sized crafted XML
expat before version 2.4.0 does not properly handle entities expansion unless an application developer uses the XML_SetE
Expat allows context-dependent attackers to cause a denial of service (crash) or possibly execute arbitrary code via a m
An issue was discovered in libexpat before 2.6.3. Rated critical severity (CVSS 9.8), this vulnerability is remotely exp
An issue was discovered in libexpat before 2.6.3. Rated critical severity (CVSS 9.8), this vulnerability is remotely exp
Exploit-DB