CVE-2026-98580 Linux CVE debrief

Who should care

Linux kernel developers and maintainers, as well as users of Linux-based systems that utilize NFC LLCP functionality, should assess their exposure to this vulnerability and apply the provided patches to mitigate potential risks.

Why it matters

The Linux kernel's NFC LLCP implementation has a race condition vulnerability that can lead to use-after-free or NULL pointer dereference. Linux kernel developers and maintainers, as well as users of Linux-based systems that utilize NFC LLCP functionality, should assess their exposure to this vulnerability and apply the provided patches to mitigate potential risks.

• Denial-of-service due to use-after-free or NULL pointer dereference
• Potential execution of arbitrary code with elevated privileges
• Verification of Linux kernel version and patch application is required to prevent exploitation

Technical summary

The Linux kernel's NFC LLCP implementation has a race condition vulnerability that can lead to use-after-free or NULL pointer dereference. The vulnerability is caused by a synchronization issue between the socket release and accept paths. The issue arises from the use of bh_lock_sock() in nfc_llcp_socket_release(), which does not synchronize with process-context lock_sock() held by nfc_llcp_accept_dequeue() during accept().

Defensive priority

Medium

Recommended defensive actions

• Review and apply the provided patches to the Linux kernel
• Ensure that the Linux kernel is updated to a version that includes the fix
• Monitor the Linux kernel's NFC LLCP implementation for potential exploitation attempts
• Perform a thorough review of the system's asset inventory to identify potential exposure
• Implement compensating controls for exposed systems while remediation is scheduled and verified
• Track exceptions and retest remediated assets to ensure the vulnerability is properly mitigated
• Verify that the Linux kernel version is compatible with the system's configuration and apply updates accordingly

Evidence notes

The vulnerability is caused by a synchronization issue between the socket release and accept paths in the Linux kernel's NFC LLCP implementation. The issue arises from the use of bh_lock_sock() in nfc_llcp_socket_release(), which does not synchronize with process-context lock_sock() held by nfc_llcp_accept_dequeue() during accept().

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.