CVE-2026-59949: yawkat LZ4 Java provides LZ4 compression for Java

Q: How do I fix CVE-2026-59949?

No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.

Q: Is CVE-2026-59949 being exploited?

CVE-2026-59949 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-59949 affect?

CVE-2026-59949 affects affected software. Severity is medium (CVSS 6.5). yawkat LZ4 Java provides LZ4 compression for Java. Prior to 1.11.1, JNI-backed XXHash implementations fail to validate the byte array object and the off and len arguments in XXHashFactory.nativeInstance().hash32().hash(), XXHashFactory.nati

Q: How urgent is CVE-2026-59949?

Priority 38/100. Remotely exploitable, no login, no user action

Routine

MEDIUM 6.5REMOTE

CVE-2026-59949 is a medium-severity flaw (CVSS 6.5) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

yawkat LZ4 Java provides LZ4 compression for Java. Prior to 1.11.1, JNI-backed XXHash implementations fail to validate the byte array object and the off and len arguments in XXHashFactory.nativeInstance().hash32().hash(), XXHashFactory.nativeInstance().hash64().hash(), XXHashFactory.nativeInstance().newStreamingHash32().update(), and XXHashFactory.nativeInstance().newStreamingHash64().update(), allowing null arrays or oversized ranges to reach na

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.5% (top 61%)
CISA exploited list	No
Weakness	CWE-476
Published	2026-08-18
Last modified	2026-10-22

Publisher (CNA): GitHub, Inc.

Last updated 2026-10-22 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Timeline

2026-08-18Published CVE record published
2026-10-22 22:10 UTCUpdated Record last modified

Exact fixes by distribution

Maven · at.yawk.lz4:lz4-java · FIXED · 1.11.1 · vulnerable: <= 1.11.0 · source

Set at.yawk.lz4:lz4-java to 1.11.1 or later in pom.xml or build.gradle, then rebuild and redeploy.

Maven · org.lz4:lz4-java · NO FIX YET · vulnerable: <= 1.8.1 · source

Fedora ELN · ntpd-rs · FIXED · 1.7.2-3.eln159 · FEDORA-2026-57e4a99310 · source

sudo dnf upgrade --advisory=FEDORA-2026-57e4a99310

Fedora 46 · moby-engine · FIXED · 29.9.2-2.fc46 · FEDORA-2026-4856be87b3 · source

sudo dnf upgrade --advisory=FEDORA-2026-4856be87b3

Debian 12 · lz4-java · NO FIX YET

Debian 13 · lz4-java · NO FIX YET

RHEL 8 · jmc:rhel8/lz4-java · DEFERRED

RHEL 8 · lz4-java · DEFERRED

RHEL 9 · jmc · DEFERRED

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-59949?

No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.

Is CVE-2026-59949 being exploited?

CVE-2026-59949 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-59949 affect?

CVE-2026-59949 affects affected software. Severity is medium (CVSS 6.5). yawkat LZ4 Java provides LZ4 compression for Java. Prior to 1.11.1, JNI-backed XXHash implementations fail to validate the byte array object and the off and len arguments in XXHashFactory.nativeInstance().hash32().hash(), XXHashFactory.nati

How urgent is CVE-2026-59949?

Priority 38/100. Remotely exploitable, no login, no user action

Software pages

Java vulnerabilities

References

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