# CVE-2026-66153: SonicWall NetExtender Linux client insecure temporary file handling

Source: https://junglewise.ai/threats/cve-2026-66153-sonicwall-netextender-linux-client-insecure-temporary-file  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-25. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-66153 · Severity: high · CVSS 7 · Published 2026-08-25

SonicWall NetExtender is a remote access client used to connect to corporate networks securely. The Linux version contains a flaw in how it handles temporary files during automatic software upgrades, allowing an attacker to manipulate file paths and potentially execute arbitrary code or modify system files with elevated privileges.

Vendors: [SonicWall](https://junglewise.ai/threats/vendors/sonicwall).

## Quick answers

**Is CVE-2026-66153 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-66153 being exploited in the wild.

**How severe is CVE-2026-66153?** High severity, with a CVSS score of 7, published 25 August 2026.

**Which products and versions are affected?** SonicWall NetExtender <unknown>.

**Is there a fix for CVE-2026-66153?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-66153 attacked?** It is attacked with local access, in a network appliance.

**Am I affected by CVE-2026-66153?** Check whether you run SonicWall NetExtender at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability exists in the NEService auto-upgrade mechanism on the Linux client, which insecurely handles temporary files without proper validation or isolation. This is a classic temporary file vulnerability (CWE-377/CWE-379) where predictable or unprotected temp file paths allow path traversal or symlink attacks. An attacker with local access to the system can manipulate file paths during the upgrade process to cause arbitrary file writes or code execution. The attack requires local system access but does not require authentication to the NetExtender service itself. Patches addressing this issue are available from SonicWall.

## Affected products

- SonicWall NetExtender <unknown>

## Timeline

- 2026-08-25: disclosed

## References

- [https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2026-0013](https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2026-0013)