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CVE-2025-66566 is an information-disclosure vulnerability in the Java-based decompressor implementations of yawkat lz4-java through version 1.10.0. Insufficient clearing of a destination buffer permits crafted compressed input to cause decompression logic to expose data left in previously used portions of a reused output buffer. Java safe, unsafe, and applicable fast decompressor paths are affected; JNI-based safe decompression is not affected. The issue is fixed in lz4-java 1.10.1.
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No public exploit code observed for this vulnerability.
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Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
14 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A network-accessible vulnerability whose CVSS vectors indicate high confidentiality impact, no integrity or availability impact, and no required privileges or user interaction. The excerpt does not identify the affected product or underlying flaw. Both vulnerability and patch publication dates are listed as December 5, 2025.
A high-severity vulnerability in the lz4-java library where decompression can leak uninitialized memory, potentially exposing sensitive data from process memory.
An information disclosure vulnerability in yawkat lz4-java's Java safe decompressor where insufficient output-buffer clearing can leak prior buffer contents to a remote attacker via crafted compressed input, potentially exposing sensitive data when applications reuse output buffers without clearing.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.