CVE-2026-53175 Linux CVE debrief

Who should care

This vulnerability affects Linux kernel users and administrators. Linux kernel developers and maintainers should also be aware of this vulnerability and take steps to ensure that their systems are patched. Additionally, users of products that rely on the Linux kernel, such as Android and other Linux-based operating systems, should also be aware of this vulnerability and take steps to patch their systems.

Technical summary

The fqdir_pre_exit() function in the Linux kernel does not properly reset the rb_fragments, fragments_tail, and last_run_head pointers after flushing a fragment queue. This can lead to a use-after-free attack, allowing an attacker to execute arbitrary code. The vulnerability is caused by the inet_frag_queue_flush() function not properly resetting these pointers. The vulnerability affects the Linux kernel and several other products that use the kernel's fragmentation handling. The vulnerability was resolved by resetting the rb_fragments, fragments_tail, and last_run_head pointers in the inet_frag_queue_flush() function.

Defensive priority

High

Recommended defensive actions

• Patch the Linux kernel with the provided patches
• Update Linux kernel to a version that includes the fix
• Use a Linux kernel version that is not vulnerable
• Monitor system logs for suspicious activity
• Implement additional security controls to prevent use-after-free attacks

Evidence notes

The vulnerability was introduced in the Linux kernel and was resolved by resetting the rb_fragments, fragments_tail, and last_run_head pointers in the inet_frag_queue_flush() function. Several patches were applied to the Linux kernel to fix this vulnerability. The vulnerability affects the Linux kernel and several other products that use the kernel's fragmentation handling.

Official resources