CVE-2026-106450 yawkat LZ4 Java: LZ4FrameInputStream reallocates block buffers for every frame, allowing CPU and GC amplification from small inputs
Attackers can cause CPU and memory exhaustion in applications using the LZ4 Java library by sending crafted compressed streams with many empty frames.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-106450?
CVE-2026-106450 is a medium-severity denial of service vulnerability in yawkat lz4-java, published on 6 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-770
Which versions are affected by CVE-2026-106450?
4 open source packages ship an affected version, including at.yawk.lz4:lz4-java and org.lz4:lz4-java.
| Package | Affected | Fixed in |
|---|---|---|
at.yawk.lz4:lz4-java Maven | All versions | 1.11.4 |
at.yawk.lz4:lz4-java Maven | All versions | 1.11.4 |
org.lz4:lz4-java Maven | All versions to 1.8.1 | None |
org.lz4:lz4-java Maven | All versions to 1.8.1 | None |
How do I fix CVE-2026-106450?
Upgrade at.yawk.lz4:lz4-java to 1.11.4 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-106450 being exploited?
There is no known exploitation of CVE-2026-106450 in the wild and no public exploit code.
Sources
Also known as CLEANSTART-2026-CE18531, CLEANSTART-2026-GP35995, CLEANSTART-2026-KZ34714, CLEANSTART-2026-LM18724, CLEANSTART-2026-QB31666, CLEANSTART-2026-TP92049 and 43 more.