CVE-2026-53025 Linux CVE debrief

Who should care

Linux kernel developers, administrators, and users who rely on the greybus: raw module should be aware of this vulnerability. The vulnerability's high severity and potential for local exploitation make it a priority for those responsible for maintaining Linux-based systems, especially those with exposure to untrusted local users.

Technical summary

The CVE-2026-53025 vulnerability is a use-after-free issue in the greybus: raw module of the Linux kernel. It arises when a raw bundle is disconnected while its character device (cdev) is still open. Upon cdev release, it leads to accessing freed memory, causing a refcount underflow and a use-after-free panic. The fix involves embedding the struct device within the structure, ensuring the cdev and device have the same lifetime, and utilizing cdev_device_add. This change guarantees that the device remains until all cdev references are released, preventing premature freeing of the structure.

Defensive priority

High priority for Linux kernel maintainers and administrators due to the vulnerability's high CVSS score of 7.8 and potential for local exploitation.

Recommended defensive actions

• Apply the official patch or update to a Linux kernel version that includes the fix for CVE-2026-53025.
• Review and update Linux kernel configurations to ensure CONFIG_INIT_ON_FREE_DEFAULT_ON=y is set or adjust as necessary.
• Monitor system logs for signs of potential exploitation attempts or use-after-free errors.
• Inventory Linux systems and prioritize patching based on exposure and criticality.
• Consider implementing compensating controls, such as restricting access to greybus: raw module functionality for untrusted users.

Evidence notes

The CVE-2026-53025 vulnerability details were obtained from the official CVE record and NVD database. The vulnerability was resolved by changes to the greybus: raw module in the Linux kernel, specifically by embedding the struct device and using cdev_device_add. The CVSS score of 7.8 indicates high severity, with AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Official resources