| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| libexpat through 2.6.1 allows an XML Entity Expansion attack when there is isolated use of external parsers (created via XML_ExternalEntityParserCreate). |
| In Expat (aka libexpat) before 2.4.5, there is an integer overflow in storeRawNames. |
| In Expat (aka libexpat) before 2.4.5, there is an integer overflow in copyString. |
| In Expat (aka libexpat) before 2.4.5, an attacker can trigger stack exhaustion in build_model via a large nesting depth in the DTD element. |
| 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. |
| Expat (aka libexpat) before 2.4.4 has a signed integer overflow in XML_GetBuffer, for configurations with a nonzero XML_CONTEXT_BYTES. |
| storeAtts in xmlparse.c in Expat (aka libexpat) before 2.4.3 has an integer overflow. |
| nextScaffoldPart in xmlparse.c in Expat (aka libexpat) before 2.4.3 has an integer overflow. |
| lookup in xmlparse.c in Expat (aka libexpat) before 2.4.3 has an integer overflow. |
| defineAttribute in xmlparse.c in Expat (aka libexpat) before 2.4.3 has an integer overflow. |
| build_model in xmlparse.c in Expat (aka libexpat) before 2.4.3 has an integer overflow. |
| addBinding in xmlparse.c in Expat (aka libexpat) before 2.4.3 has an integer overflow. |
| In doProlog in xmlparse.c in Expat (aka libexpat) before 2.4.3, an integer overflow exists for m_groupSize. |
| Expat through 2.8.3 contains an out-of-bounds read vulnerability that allows attackers to trigger memory corruption by processing XML with external entity parsers created via XML_ExternalEntityParserCreate. A struct size mismatch between ELEMENT_TYPE members causes storeAtts to read the attIndex member past allocated memory boundaries, resulting in failure to normalize whitespace in non-CDATA attributes or a wild pointer dereference causing a segfault. This vulnerability was introduced by the fix for CVE-2026-66046. |
| libexpat versions 2.7.2 through 2.8.5 contain an integer overflow vulnerability in expat_realloc() function on 32-bit platforms when computing allocation sizes. Attackers supplying malicious XML to applications parsing with vulnerable libexpat can cause heap buffer overflow, memory corruption, or denial of service. |
| Expat before 2.8.5 fails to validate that a high surrogate in UTF-16 input is followed by a low surrogate, allowing malformed UTF-16 sequences to be accepted. Attackers can supply UTF-16 encoded XML containing lone high surrogates that consume the following code unit, causing Expat to pass unpaired surrogates to applications built with XML_UNICODE and to silently replace input characters in other builds. |
| Expat through 2.8.3 contains a denial of service vulnerability caused by quadratic algorithmic complexity in the storeAtts() function in xmlparse.c, where processing N specified attributes with non-normalized values triggers an O(N^2) linear scan of elementType->defaultAtts to determine CDATA status. A remote unauthenticated attacker can supply a single well-formed XML document of a few megabytes to an application parsing untrusted XML to cause excessive CPU consumption, resulting in denial of service without requiring authentication, external entity resolution, or non-default parser options. |
| In libexpat before 2.8.1, the computational complexity of attribute name collision checks allows a denial of service via moderately sized crafted XML input. |
| In libexpat 2.8.2 and 2.8.3 before 2.8.4, misinterpretation of getentropy's return code leads to insufficient entropy, which results in being vulnerable to hash flooding attacks, causing a denial of service via crafted XML content. |
| libexpat before 2.8.4 lacks handler call depth tracking with custom encoding callbacks. Thus, a use-after-free can occur. NOTE: this is similar to CVE-2026-50219, CVE-2026-56131 and CVE-2026-56412. |
