CVE-2026-74640 Linux CVE debrief

Who should care

Linux kernel developers and maintainers, Linux distribution maintainers, and users of Linux-based systems should be aware of this vulnerability and take necessary actions to mitigate it. They should review and apply patches or updates as needed, verify Linux kernel versions, and monitor system logs for potential exploitation attempts.

Why it matters

A vulnerability in the Linux kernel's ALSA FCP component can lead to an out-of-bounds write, allowing local attackers to achieve high confidentiality, integrity, and availability impacts. Defenders should verify Linux kernel versions and apply patches or updates as needed.

• Local attackers with low privileges may be able to exploit this vulnerability to achieve high confidentiality, integrity, and availability impacts.
• Successful exploitation requires verification from official Linux kernel sources.
• Defenders should verify Linux kernel versions and apply patches or updates as needed.
• Exposure and actual exploitation require further verification.

Technical summary

The vulnerability exists in the Linux kernel's ALSA FCP component, where a user-supplied Level Meter map size was not properly bounded, leading to an out-of-bounds write in the `fcp_meter_ctl_get()` function. The fix involves bounding the user-supplied Level Meter map size and updating the control's channel count. This issue allows local attackers to potentially achieve high confidentiality, integrity, and availability impacts. Linux kernel developers and maintainers should review and apply patches or updates as needed.

Defensive priority

High

Recommended defensive actions

• Review and apply the provided source code changes to ensure the fix is implemented
• Verify the Linux kernel version and update to a fixed version if necessary
• Monitor system logs for potential exploitation attempts
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review compensating controls for exposed systems while remediation is scheduled and verified
• 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

Evidence notes

The CVE record and source item provide details on the vulnerability, including its description, affected versions, and references to source code changes. The Linux kernel's ALSA FCP component was vulnerable to an out-of-bounds write due to improper bounding of the user-supplied Level Meter map size. Official CVE Program records and NIST NVD detail pages offer additional information on the vulnerability. Defenders should verify Linux kernel versions and apply patches or updates as needed, while also monitoring system logs for potential

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.