CVE-2026-59949

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.5%, top 63% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.5Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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 native code, read outside the Java array, and fatally terminate the JVM. This issue is fixed in version 1.11.1.

CVSS v3
6.5
EG Score
6.5(medium)
EG Risk
29(Track)
EG Risk 29/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity65% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
38%
KEV
Not listed

Published

July 24, 2026

Last Modified

August 18, 2026

Advisory Details (3)

Auto-updated Aug 18, 2026
Patch available. Sources: github_release, github, github_commit.
github Patch Available

Native XXHash implementations can crash the JVM when passed invalid byte array ranges · Advisory · yawkat/lz4-java · GitHub

https://github.com/yawkat/lz4-java/security/advisories/GHSA-xx22-p4ch-683r
github_release Patch Available

lz4-java v1.11.1

Patch available: yawkat/lz4-java v1.11.1

https://github.com/yawkat/lz4-java/releases/tag/v1.11.1
github_commit Patch Available

commit dbd86d04b8dd (yawkat/lz4-java)

Patch available: yawkat/lz4-java v1.11.1 (contains commit dbd86d04b8dd)

https://github.com/yawkat/lz4-java/commit/dbd86d04b8dd716e1c2bc626be54189997d910da

Vendor Advisories for CVE-2026-59949(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(2 across 1 ecosystem)
Maven(2)
PackageVulnerable rangeFixed inDependents
at.yawk.lz4:lz4-java1.10.0 ... 1.9.0 (8 versions)1.11.1—
org.lz4:lz4-java1.4 ... 1.8.1 (10 versions)——

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 11× in last 7d / 16× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-26 14:46 UTCEPSS rescore
  2. 2026-08-25 18:47 UTCEG score recompute
  3. 2026-08-25 13:49 UTCEPSS rescore
  4. 2026-08-24 19:03 UTCEG score recompute
  5. 2026-08-23 19:18 UTCEG score recompute
  6. 2026-08-23 00:19 UTCEPSS rescore
  7. 2026-08-22 19:33 UTCEG score recompute
  8. 2026-08-21 23:49 UTCEPSS rescore
  9. 2026-08-21 19:48 UTCEG score recompute
  10. 2026-08-20 22:55 UTCEPSS rescore
  11. 2026-08-19 20:18 UTCEG score recompute
  12. 2026-08-19 17:04 UTCEPSS rescore
  13. 2026-08-18 18:25 UTCEG score recompute
  14. 2026-08-18 18:00 UTCEG score recompute
  15. 2026-08-18 15:34 UTCEG score recompute
  16. 2026-07-31 08:34 UTCEG score recompute
  17. 2026-07-27 09:28 UTCEG score recompute
  18. 2026-07-24 17:13 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-59949?
CVE-2026-59949 is a medium vulnerability published on July 24, 2026. 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(),…
When was CVE-2026-59949 disclosed?
CVE-2026-59949 was first published in the National Vulnerability Database on July 24, 2026, with the most recent update on August 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-59949 actively exploited?
CVE-2026-59949 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 62.5% of all scored CVEs.
What is the CVSS score of CVE-2026-59949?
CVE-2026-59949 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-59949?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-59949, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-59949

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