xz is a pure golang package for reading and writing xz-compressed files. Prior to version 0.5.14, it is possible to put data in front of an LZMA-encoded byte stream without detecting the situation while reading the header. This can lead to increased memory consumption because the current implementation allocates the full decoding buffer directly after reading the header. The LZMA header doesn't include a magic number or has a checksum to detect such an issue according to the specification. Note that the code recognizes the issue later while reading the stream, but at this time the memory allocation has already been done. This issue has been patched in version 0.5.14.

xz is a compression and decompression library focusing on the xz format completely written in Go. The function readUvarint used to read the xz container format may not terminate a loop provide malicous input. The problem has been fixed in release v0.5.8. As a workaround users can limit the size of the compressed file input to a reasonable size for their use case. The standard library had recently the same issue and got the CVE-2020-16845 allocated.