Threat Intelligence Database

CVE-2026-66046 is a denial of service vulnerability in libexpat through version 2.8.3. It arises from inefficient algorithmic complexity in the storeAtts() function of xmlparse.c, where processing attributes with non-normalized values causes quadratic time complexity. A remote unauthenticated attacker can exploit this by sending a crafted XML document to cause excessive CPU usage and denial of service without needing authentication or special parser options.

CVE-2026-76957 is a use-after-free vulnerability in libexpat versions prior to 2.8.4. The flaw arises because libexpat lacks handler call depth tracking when using custom encoding callbacks, which can lead to memory being freed prematurely and subsequently accessed. This vulnerability is related to similar issues identified in other CVEs for libexpat. The CVSS score is 4.9, indicating a medium severity level.

CVE-2026-76956 is a vulnerability in libexpat versions 2.8.2 and 2.8.3 prior to 2.8.4 where the return code of the getentropy function is misinterpreted. This leads to insufficient entropy being used, making the software vulnerable to hash flooding attacks that can cause denial of service through crafted XML content.

libexpat before 2.8.3 has an out-of-bounds read and resultant infinite loop because low surrogates are treated the same as high surrogates during Unicode processing in the *_toUtf16 functions.

xmlwf in libexpat before 2.8.2 has an integer overflow in endDoctypeDecl via NOTATION declarations.

xmlwf in libexpat before 2.8.2 has an integer overflow in resolveSystemId.

xmlwf in libexpat before 2.8.2 has an integer overflow for the output filename when -d outputDir is used.

libexpat before 2.8.2 has an integer overflow in copyString.

libexpat before 2.8.2 has an integer overflow in doProlog that is related to storeEntityValue and entity textLen.

libexpat before 2.8.2 has an integer overflow in getAttributeId.