It was discovered that XZ Utils incorrectly handled certain memory
allocation failures when reinitializing decoders for specific compressed
file formats. An attacker could possibly use this issue to trigger an
invalid memory write, resulting in a denial of service or arbitrary code
execution.
XZ Utils provide a general-purpose data-compression library plus command-line tools. Prior to version 5.8.3, if lzma_index_decoder() was used to decode an Index that contained no Records, the resulting lzma_index was left in a state where where a subsequent lzma_index_append() would allocate too little memory, and a buffer overflow would occur. This issue has been patched in version 5.8.3.