NULL Pointer Dereference Affecting org.lz4:lz4-java package, versions [0,]

org.lz4:lz4-java is a Java port of the LZ4 compression algorithm and the xxHash hashing algorithm.

Affected versions of this package are vulnerable to NULL Pointer Dereference and out-of-bounds read in the native XXHash implementations reached through XXHashFactory.nativeInstance(), where SafeUtils.checkRange() skips all array validation when len == 0 and lets invalid references or ranges reach the JNI code. An attacker can crash the JVM, and expose in-process memory before the crash, by passing a null array with zero length or an oversized length to the native hash32(), hash64(), or streaming update() methods, which then read outside the array bounds in native code. Exploitation requires the application to let the attacker influence the array reference or the offset and length arguments to a native XXHash call, not merely the contents of a valid array, and only the native JNI instances are affected.

This vulnerability can be avoided by using XXHashFactory.safeInstance() instead of nativeInstance(), which computes the hash in pure Java and never crosses the JNI boundary where the flaw occurs.

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