---
title: "CVE-2026-87877: zstd-jni - Use After Free"
description: "zstd-jni < 1.5.7-14 contains a use-after-free caused by failure to validate closed state in setDict, setLongMax, setLevel, and setRefMultipleDDicts methods, letting attackers corrupt memory or crash JVM by writing through freed pointers."
url: https://panop.io/threat-heartbeat/CVE-2026-87877/
---

# CVE-2026-87877 zstd-jni - Use After Free

zstd-jni < 1.5.7-14 contains a use-after-free caused by failure to validate closed state in setDict, setLongMax, setLevel, and setRefMultipleDDicts methods, letting attackers corrupt memory or crash JVM by writing through freed pointers.

CVSS base score 7.7 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.20% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-87877)

## Details

Type

Use After Free

Impact

Denial Of Service, Remote Code Execution

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

Published

9 September 2026

Updated

15 October 2026

Weakness

[CWE-416](https://cwe.mitre.org/data/definitions/416.html)

## Vendor fix

Update to version 1.5.7-14 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-87877](https://nvd.nist.gov/vuln/detail/CVE-2026-87877)
- [https://github.com/luben/zstd-jni](https://github.com/luben/zstd-jni)
- [https://github.com/luben/zstd-jni/blob/v1.5.7-13/src/main/java/com/github/luben/zstd/BaseZstdBufferDecompressingStreamNoFinalizer.java](https://github.com/luben/zstd-jni/blob/v1.5.7-13/src/main/java/com/github/luben/zstd/BaseZstdBufferDecompressingStreamNoFinalizer.java)
- [https://github.com/luben/zstd-jni/blob/v1.5.7-13/src/main/java/com/github/luben/zstd/ZstdInputStreamNoFinalizer.java](https://github.com/luben/zstd-jni/blob/v1.5.7-13/src/main/java/com/github/luben/zstd/ZstdInputStreamNoFinalizer.java)
- [https://github.com/luben/zstd-jni/commit/0827ed02551bbd8d6f8e4bbff99d83bf50f91938](https://github.com/luben/zstd-jni/commit/0827ed02551bbd8d6f8e4bbff99d83bf50f91938)
- [https://github.com/luben/zstd-jni/commit/393d7311766abbc285b149302c0fe1f94b16d555](https://github.com/luben/zstd-jni/commit/393d7311766abbc285b149302c0fe1f94b16d555)
- [https://github.com/luben/zstd-jni/commit/f38f9a1563113d96d0fc38baee543f7457dd8a8e](https://github.com/luben/zstd-jni/commit/f38f9a1563113d96d0fc38baee543f7457dd8a8e)
- [https://github.com/luben/zstd-jni/releases/tag/v1.5.7-14](https://github.com/luben/zstd-jni/releases/tag/v1.5.7-14)
- [https://github.com/luben/zstd-jni/security/advisories/GHSA-2jw3-mg7f-vw4q](https://github.com/luben/zstd-jni/security/advisories/GHSA-2jw3-mg7f-vw4q)
- [https://www.vulncheck.com/advisories/zstd-jni-1.3.8-4-through-1.5.7-13-use-after-free-via-setters-called-after-close](https://www.vulncheck.com/advisories/zstd-jni-1.3.8-4-through-1.5.7-13-use-after-free-via-setters-called-after-close)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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