# CVE-2026-45657: Microsoft Windows Kernel use after free remote code execution

Source: https://junglewise.ai/threats/cve-2026-45657-microsoft-windows-kernel-use-after-free-remote-code-execution  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-09. Updated: 2026-06-09  
License: CC BY 4.0 with a link back

CVE-2026-45657 · Severity: critical · CVSS 9.8 · Published 2026-06-09

A critical vulnerability has been identified in the Windows operating system kernel, which manages the core operations of the computer. This flaw allows a remote attacker to gain full control over a system without needing any user interaction or login credentials. An exploit could lead to a total compromise of the affected server or workstation, resulting in data theft, service disruption, or the installation of malware.

## Quick answers

**Is CVE-2026-45657 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-45657 being exploited in the wild.

**How severe is CVE-2026-45657?** Critical severity, with a CVSS score of 9.8, published 9 June 2026.

**Which products and versions are affected?** Microsoft Windows All supported versions.

**Is there a fix for CVE-2026-45657?** 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-2026-45657 attacked?** It is attacked over the network, in an operating system.

**Am I affected by CVE-2026-45657?** Check whether anything you run is named in the advisory. 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

This vulnerability is classified as a Use-After-Free (CWE-416) and Heap-based Buffer Overflow (CWE-122) within the Windows Kernel. The flaw is triggered when the kernel improperly handles objects in memory, allowing an attacker to send specially crafted network packets to a vulnerable system. Because the vulnerability exists at the kernel level and is reachable over the network without authentication (AV:N/AC:L/PR:N/UI:N), a successful exploit grants the attacker SYSTEM-level privileges. This can lead to full remote code execution (RCE). Microsoft has released security updates to address this issue via the MSRC.

## Affected products

- Microsoft Windows All supported versions

## Timeline

- 2026-06-09: disclosed
- 2026-06-09: advisory

## References

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45657](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45657)