CVE-2026-106449: yawkat LZ4 Java: LZ4BlockInputStream with stopOnEmptyBlock=false recurses once per empty block, causing StackOverflowError

CVE-2026-106449 · Severity: low · CVSS 3.7 · Published 2026-10-06

yawkat LZ4 Java provides LZ4 compression for Java. Prior to 1.11.4, net.jpountz.lz4.LZ4BlockInputStream configured with stopOnEmptyBlock set to false handles each well-formed empty LZ4Block by recursively calling refill(), allowing a long sequence of empty blocks in an attacker-controlled compressed stream to exhaust the decoding thread's stack and throw StackOverflowError. The default stopOnEmptyBlock setting is true and is not affected, and the issue does not cause memory corruption. This issue is fixed in version 1.11.4.

Technologies: at.yawk.lz4:lz4-java (Maven), org.lz4:lz4-java (Maven). Vendors: Maven.

Quick answers

Is CVE-2026-106449 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-106449 being exploited in the wild.
How severe is CVE-2026-106449?
Low severity, with a CVSS score of 3.7, published 6 October 2026.
Which products and versions are affected?
at.yawk.lz4:lz4-java (Maven) <= 1.11.3, ECOSYSTEM:introduced=0,fixed=1.11.4; org.lz4:lz4-java (Maven) <= 1.8.1, ECOSYSTEM:introduced=0,last_affected=1.8.1.
Is there a fix for CVE-2026-106449?
Yes. at.yawk.lz4:lz4-java (Maven): upgrade to 1.11.4 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
Am I affected by CVE-2026-106449?
Check whether you run at.yawk.lz4:lz4-java (Maven) or org.lz4:lz4-java (Maven) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • at.yawk.lz4:lz4-java (Maven): upgrade to 1.11.4 or later
    # set at.yawk.lz4:lz4-java to 1.11.4 in your pom.xml or build.gradle

Affected products

  • at.yawk.lz4:lz4-java (Maven) <= 1.11.3, ECOSYSTEM:introduced=0,fixed=1.11.4
  • org.lz4:lz4-java (Maven) <= 1.8.1, ECOSYSTEM:introduced=0,last_affected=1.8.1

Identifiers

  • CVE-2026-106449
  • GHSA-343h-94h5-c4wr

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.