XML external entity (XXE) vulnerability in the xmlStringLenDecodeEntities function in parser.c in libxml2 before 2.9.4, when not in validating mode, allows context-dependent attackers to read arbitrary files or cause a denial of service (resource consumption) via unspecified vectors.
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.