# CVE-2026-59565: Local and kernel denial-of-service

> A remote buffer overflow in Zscaler Client Connector for Windows allows attackers to cause local and kernel denial-of-service conditions.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 24 Aug 2026
- **Updated:** 24 Aug 2026
- **Also known as:** GHSA-c34f-p2fw-3mjr

## What is CVE-2026-59565?

CVE-2026-59565 is a high-severity denial of service vulnerability in Zscaler Client Connector, published on 24 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A remotely exploitable buffer overflow bug can cause a local and kernel denial-of-service attack on affected versions of Zscaler Client Connector on Windows.

Weakness: CWE-229 (Improper Handling of Values)

## Which versions are affected by CVE-2026-59565?


## How do I fix CVE-2026-59565?

No fix has been published for CVE-2026-59565 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-59565 being exploited?

There is no known exploitation of CVE-2026-59565 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-59565 and fix it if it is affected.

What it is: CVE-2026-59565 is a high-severity denial of service vulnerability in Zscaler Client Connector, published on 24 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-59565 in the wild and no public exploit code.

Affected product: Zscaler Client Connector. 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-2026-59565/ (Markdown: https://insights.sbomify.com/CVE-2026-59565/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-59565
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-59565
- OSV: https://osv.dev/vulnerability/CVE-2026-59565

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-59565/
Summaries are generated and may contain mistakes; the official description above is the record.