What’s Vulnerable › Vulnerabilities

CVE-2026-106450: yawkat LZ4 Java: LZ4FrameInputStream reallocates block buffers for every frame, allowing CPU and GC amplification from small inputs

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-06 · updated 2026-10-09
• Weakness: CWE-770

Description

yawkat LZ4 Java provides LZ4 compression for Java. Prior to 1.11.4, net.jpountz.lz4.LZ4FrameInputStream readHeader() allocates two new 4 MiB block buffers whenever a maximum-block-size frame header is read, and the default concatenated-frame mode allows attacker-controlled streams containing many minimal empty frames to trigger roughly 8 MiB of allocation for every 11 input bytes. The stream produces no decompressed output while consuming CPU and garbage-collection time, so decompressed-size limits do not mitigate the issue; readSingleFrame mode is not affected. This issue is fixed in version 1.11.4.

Affected products

• yawkat lz4-java: before 1.11.4

References

• https://github.com/yawkat/lz4-java/commit/2acc0ec1ead226145c62a817c18c8ed49233a283
• https://github.com/yawkat/lz4-java/releases/tag/v1.11.4
• https://github.com/yawkat/lz4-java/security/advisories/GHSA-gm45-99xc-r7wv

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