CVE-2026-64523: Critical Vulnerability in Linux Kernel

Introduction

A critical vulnerability has been identified in the Linux kernel, which may affect system stability and security. This vulnerability allows long-lived file references to be mishandled, potentially leading to integrity and security issues.

What happened?

The vulnerability resides in the function handshake_nl_accept_doit(), which requires a file pointer to survive a critical window between two operations. Improper management of file references can result in premature socket destruction, even when references are still held.

How the vulnerability works

The vulnerability occurs due to how file references are managed during the handshake process. When a handshake operation is initiated, the function must maintain a reference to the corresponding socket. If the reference is not properly maintained, a race condition may occur that leads to socket destruction, causing system failures.

What is the real impact?

The impact of this vulnerability is considered critical, as it may allow an attacker to cause service failures that rely on the Linux kernel, compromising system availability and integrity. Exploitation of this vulnerability may result in denial of service or other undesirable behaviors.

Which versions are affected?

• linux kernel ≥ 6.4 < 6.6.160
• linux kernel ≥ 6.7 < 6.12.93
• linux kernel ≥ 6.13 < 6.18.44
• linux kernel ≥ 6.19 < 7.0.12
• linux kernel 7.1

How to fix

1. Check your Linux kernel version.
2. Update to a patched version of the kernel as recommended by the vendor.
3. Reboot the system after the update to ensure changes are applied.
4. Monitor security advisories for future updates and patches.

Mitigation while you update

While an update is not possible, it is recommended to:

• Limit system access to authorized users only.
• Implement monitoring to detect anomalous behavior on the system.
• Review kernel security configurations to minimize exposure to attacks.

Conclusion

The CVE-2026-64523 vulnerability in the Linux kernel is critical and should be addressed urgently. Updating to a patched version is the best way to ensure the security and stability of your system.