CVE-2026-63956 Linux CVE debrief

Who should care

Users of the Linux kernel, Linux kernel developers, and security teams should verify their systems for potential vulnerabilities and ensure that the interrupt-out endpoint max packet size is at least eight bytes.

Technical summary

A vulnerability was found in the Linux kernel's USB: serial: cypress_m8 driver. The vulnerability could lead to memory corruption with small endpoints. To avoid user-controlled slab corruption or NULL-pointer dereference, the interrupt-out endpoint max packet size must be at least eight bytes. Users should verify the Linux kernel version and check for potential vulnerabilities. This issue requires verification of system configurations and defensive measures to mitigate potential impacts, including reviewing system logs for unusual activity and ensuring that the interrupt-out endpoint max packet size is properly configured. Additionally, users should confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.

Defensive priority

Medium

Recommended defensive actions

• Verify and apply the patch for the Linux kernel's USB: serial: cypress_m8 driver
• Ensure that the interrupt-out endpoint max packet size is at least eight bytes
• Monitor systems for potential vulnerabilities
• Review system logs for unusual activity
• Verify the Linux kernel version
• Check for potential vulnerabilities
• Perform a thorough review of system configurations

Evidence notes

The CVE record was published on 2026-07-19T16:17:14.410Z and has not been modified since then. The NVD entry is currently Received. Users should verify the Linux kernel version and check for potential vulnerabilities. Defensive verification tasks include reviewing system logs for unusual activity and ensuring that the interrupt-out endpoint max packet size is at least eight bytes.

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.