CVE-2026-89471 Linux CVE debrief

Who should care

Linux kernel developers and maintainers, Linux distribution vendors, and users of affected Linux kernel versions should assess exposure and apply patches. Additionally, system administrators, security teams, and operators of affected systems should review system configurations, monitor system logs, and implement compensating controls as needed.

Why it matters

CVE-2026-89471 is a Linux kernel vulnerability in the cros_usbpd-charger driver that allows a slab out-of-bounds write due to insufficient validation of EC-reported port counts. Defenders should verify and apply patches, review system configurations, and monitor system logs.

• Verify and apply patches to prevent potential slab out-of-bounds writes
• Review system configurations and kernel versions for potential exposure
• Monitor system logs for signs of exploitation

Technical summary

The Linux kernel cros_usbpd-charger driver does not properly validate EC-reported port counts, allowing for a potential slab out-of-bounds write. The issue arises from the driver's failure to check port counts against the size of the ports array. This vulnerability can be mitigated by applying the provided patches. The EC-reported port counts are stored in u8 values, and a sanity check compares the two EC-reported values against each other. However, this check does not prevent a malfunctioning, malicious, or compromised EC from reporting port counts larger than the array size.

Defensive priority

Verify and apply patches for the Linux kernel cros_usbpd-charger driver to prevent potential slab out-of-bounds writes.

Recommended defensive actions

• Verify and apply patches for the Linux kernel cros_usbpd-charger driver
• Review system configurations and kernel versions for potential exposure
• Monitor system logs for signs of exploitation
• Perform a thorough review of the system to identify potential vulnerabilities
• Implement compensating controls for exposed systems while remediation is scheduled and verified
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Review and update asset inventory to ensure all affected systems are accounted for

Evidence notes

The CVE record and source references indicate a vulnerability in the Linux kernel cros_usbpd-charger driver. The issue involves insufficient validation of EC-reported port counts, potentially leading to a slab out-of-bounds write.

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.