Use After Free in Luben Zstd-Jni

CVE-2026-87877

zstd-jni versions before 1.5.7-14 fail to validate closed state in setDict, setLongMax, setLevel and setRefMultipleDDicts methods of stream classes. Attackers can call these methods on closed streams to write through freed native pointers, corrupting unrelated objects or crashing the JVM.

Vulnerability class: Use-After-Free

CVSS v3 metric

CVSS v3 base score 7.7 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-87877?
CVE-2026-87877 is a high-severity vulnerability in Luben Zstd-Jni, classified under Use After Free. CVSS score: 7.7/10. Published 2026-09-09.
How severe is CVE-2026-87877?
High severity. CVSS v3 base score is 7.7 out of 10.