CVE-2026-64496 Linux CVE debrief

Who should care

Linux kernel developers and maintainers, Linux distribution maintainers, users of Linux-based systems, and security teams responsible for vulnerability management and monitoring. They should review and apply patches, verify kernel versions, and monitor for potential issues.

Why it matters

A race condition vulnerability in the Linux kernel's IIO event FIFO reset mechanism requires attention from Linux kernel developers, maintainers, and users to ensure the fix is applied and potential issues are monitored.

• Data corruption or unexpected behavior in the Linux kernel's IIO event FIFO mechanism
• Potential denial of service (DoS) due to incorrect FIFO index advancement
• Need for verification of Linux kernel versions and patches to ensure fix is applied

Technical summary

The Linux kernel's IIO event FIFO reset mechanism is vulnerable to a race condition. The `iio_event_getfd()` function creates an event file descriptor and resets the event FIFO before the file descriptor is fully installed in the process's fd table. This can lead to parallel execution of `kfifo_to_user()` and `kfifo_reset_out()`, potentially causing the FIFO's `out` index to be advanced incorrectly.

Defensive priority

Medium

Recommended defensive actions

• Review and apply the provided patches to the Linux kernel to fix the vulnerability
• Ensure that the Linux kernel is updated to a version that includes the fix
• Monitor the Linux kernel's IIO event FIFO mechanism for potential issues
• Verify Linux kernel versions and patches to ensure the fix is applied
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The vulnerability is caused by a race condition in the `iio_event_getfd()` function. The function creates an event file descriptor using `anon_inode_getfd()`, which allocates a new fd and installs it in the process's fd table. However, the IIO code resets the event FIFO after `anon_inode_getfd()` has returned, but before `IIO_GET_EVENT_FD_IOCTL` has copied the fd number to userspace. This can lead to parallel execution of `kfifo_to_user()` and `kfifo_reset_out()`, potentially causing the FIFO's `out` index to be advanced incorrectly.

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.