# CVE-2026-89045: zstd-jni 1.4.8-4 through 1.5.7-13 Denial of Service via Negative Length

> Attackers can cause a denial of service in zstd-jni by passing negative length values, triggering infinite loops that block thread access.

- **Severity:** Medium 5.1 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 10 Sep 2026
- **Updated:** 15 Sep 2026
- **Also known as:** CLEANSTART-2026-CN35932, CLEANSTART-2026-FK53142, CLEANSTART-2026-OP88753, CLEANSTART-2026-PD97726, CLEANSTART-2026-WP99791, DEBIAN-CVE-2026-89045, GHSA-9jx2-gfp9-phfm, GHSA-r8cw-jvfx-h6x5, UBUNTU-CVE-2026-89045

## What is CVE-2026-89045?

CVE-2026-89045 is a medium-severity denial of service vulnerability in luben zstd-jni, published on 10 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

zstd-jni versions 1.4.8-4 through 1.5.7-13 fail to validate negative length parameters in ZstdInputStreamNoFinalizer.read(), allowing attackers to trigger infinite loops. Attackers can pass negative length values to cause the read method to spin indefinitely while holding the stream monitor, blocking all other threads from accessing the stream.

Weakness: CWE-835 (Loop with Unreachable Exit Condition)

## Which versions are affected by CVE-2026-89045?


## How do I fix CVE-2026-89045?

Upgrade to a fixed version.

## Is CVE-2026-89045 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-89045 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89045 and fix it if it is affected.

What it is: CVE-2026-89045 is a medium-severity denial of service vulnerability in luben zstd-jni, published on 10 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-89045 exists.

Affected product: luben zstd-jni. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-89045/ (Markdown: https://insights.sbomify.com/CVE-2026-89045/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89045
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89045
- OSV: https://osv.dev/vulnerability/CVE-2026-89045

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89045/
Summaries are generated and may contain mistakes; the official description above is the record.