# CVE-2026-70027: Windows Subsystem for Linux heap buffer overflow privilege escalation

Source: https://junglewise.ai/threats/cve-2026-70027-heap-based-buffer-overflow-in-windows-subsystem-for-linux-allows  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-13. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-70027 · Severity: high · CVSS 7.8 · Published 2026-10-13

Windows Subsystem for Linux (WSL) contains a heap buffer overflow vulnerability that allows an authorized local user to escalate their privileges to a higher level of access. An attacker with legitimate login credentials could exploit this flaw to gain elevated system permissions and take control of the affected system.

Technologies: [Microsoft Windows Subsystem For Linux](https://junglewise.ai/threats/technologies/windows-subsystem-for-linux). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-2026-70027 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-70027 being exploited in the wild.

**How severe is CVE-2026-70027?** High severity, with a CVSS score of 7.8, published 13 October 2026.

**Which products and versions are affected?** Microsoft Windows Subsystem for Linux.

**Is there a fix for CVE-2026-70027?** 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-2026-70027 attacked?** It is attacked with local access, in an operating system.

**Am I affected by CVE-2026-70027?** Check whether you run Microsoft Windows Subsystem For Linux. 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

A heap-based buffer overflow exists in Windows Subsystem for Linux that can be triggered by an authenticated local attacker. The vulnerability permits privilege escalation from a standard user context to a higher privilege level. This is a memory corruption issue requiring local access with valid credentials; no fix information is publicly available yet.

## Affected products

- Microsoft Windows Subsystem for Linux

## Timeline

- 2026-10-13: disclosed

## References

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-70027](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-70027)

## Related threats

- [Windows Subsystem for Linux use-after-free privilege escalation](https://junglewise.ai/threats/cve-2026-88237-use-after-free-in-windows-subsystem-for-linux-allows-an)
- [Windows Subsystem for Linux out-of-bounds read privilege escalation](https://junglewise.ai/threats/cve-2026-119846-out-of-bounds-read-in-windows-subsystem-for-linux-allows-an)
- [Microsoft Windows Subsystem for Linux heap buffer overflow](https://junglewise.ai/threats/cve-2026-119834-heap-based-buffer-overflow-in-windows-subsystem-for-linux-allows)
- [Docker Desktop for Windows WSL2 seccomp bypass via 32-bit socketcall](https://junglewise.ai/threats/cve-2026-112917-in-docker-desktop-for-windows-with-the-wsl2-backend-an)
- [Microsoft Windows Subsystem for Linux information disclosure](https://junglewise.ai/threats/cve-2026-96206-use-of-uninitialized-resource-in-windows-subsystem-for-linux)