Executive brief
lz4-java is a popular compression library for Java applications. A vulnerability in its XXHash hashing component allows an attacker to crash the application (denial of service) or potentially view sensitive memory by providing malformed data ranges. This could lead to service outages or minor data exposure in systems that allow users to specify data offsets or lengths for hashing.
Technical details
The JNI-backed XXHash implementations in lz4-java fail to properly validate byte array references, offsets, and lengths before passing them to native code. Specifically, the streaming JNI implementations lacked validation for 'bytes', 'off', or 'len' arguments, while non-streaming implementations failed to catch null arrays when the length was zero. An attacker who can control these parameters can trigger a NULL pointer dereference (CWE-476) or an out-of-bounds read (CWE-125), leading to a fatal JVM crash or potential exposure of in-process memory. The issue is fixed in version 1.11.1 by adding proper range and null checks before JNI calls.
Affected products
- at.yawk.lz4 lz4-java <= 1.11.0
- org.lz4 lz4-java <= 1.8.1
Timeline
- 2026-07-06: disclosed
- 2026-07-24: advisory: GitHub Advisory published
- 2026-07-24: patched