CVE-2009-3720
MediumExploitation Probability (EPSS)
Very high risk98th percentile - higher than 98% of all known CVEs
Summary
The updatePosition function in libexpat (Expat 2.0.1) has a buffer over-read vulnerability. Crafted UTF-8 sequences in an XML document can cause an application crash.
Risk Assessment
An attacker can remotely cause a denial of service (DoS) by sending a malicious XML document to an application using the vulnerable Expat version, potentially disrupting system operations.
Recommendation
Update the Expat library to version 2.0.2 or later, and update all dependent software (Python, PyXML, w3c-libwww).
Other vulnerabilities in Expat
See all- CVE-2022-25315Critical
In Expat (aka libexpat) before 2.4.5, there is an integer overflow in storeRawNames.
- CVE-2022-25314High
In Expat (libexpat) before 2.4.5, there is an integer overflow in copyString.
- CVE-2022-25236Critical
In xmlparse.c in Expat (aka libexpat) before 2.4.5, attackers can insert namespace-separator characters into namespace URIs.
- CVE-2022-25235Critical
In xmltok_impl.c in Expat (aka libexpat) before 2.4.5 lacks certain validation of encoding, such as checks for whether a UTF-8 character is valid in a certain context.
- CVE-2022-23990High
Expat (libexpat) before 2.4.4 has an integer overflow in the doProlog function. This may lead to improper XML parser behavior.
- CVE-2022-23852Critical
Expat (aka libexpat) before 2.4.4 has a signed integer overflow in XML_GetBuffer, for configurations with a nonzero XML_CONTEXT_BYTES.
- CVE-2022-22824Critical
The defineAttribute function in xmlparse.c in Expat (libexpat) before 2.4.3 has an integer overflow. This may lead to incorrect behavior of the XML parser.
- CVE-2022-22823Critical
The build_model function in xmlparse.c in Expat (libexpat) before 2.4.3 has an integer overflow. This may lead to incorrect behavior of the XML parser.
- CVE-2022-22822Critical
addBinding in xmlparse.c in Expat (aka libexpat) before 2.4.3 has an integer overflow.
- CVE-2021-45960High
In Expat (libexpat) before 2.4.3, a left shift by 29 or more bits in the storeAtts function in xmlparse.c can lead to realloc misbehavior, such as allocating too few bytes or only freeing memory.
Original NVD description (English source)
The updatePosition function in lib/xmltok_impl.c in libexpat in Expat 2.0.1, as used in Python, PyXML, w3c-libwww, and other software, allows context-dependent attackers to cause a denial of service (application crash) via an XML document with crafted UTF-8 sequences that trigger a buffer over-read, a different vulnerability than CVE-2009-2625.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS