CVE-2026-80931 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. The vulnerability affects the Linux kernel's w1_f19_i2c_master_transfer function and could potentially lead to a denial of service (DoS) or code execution. It is essential to review and apply the provided patches to the Linux kernel and ensure that the Linux kernel is up-

Why it matters

A vulnerability in the Linux kernel's w1_f19_i2c_master_transfer function allows for an out-of-bounds read when handling I2C block reads. This could potentially lead to a denial of service (DoS) or code execution.

• Potential buffer overflow and out-of-bounds read
• Possible denial of service (DoS) or code execution

Technical summary

The Linux kernel's w1_f19_i2c_master_transfer function does not properly validate the length of I2C block reads, allowing for out-of-bounds reads. The function reads a length byte from the device and uses it to read additional bytes into a buffer without checking if the length is within the buffer's bounds. This vulnerability could potentially lead to a denial of service (DoS) or code execution. The issue was resolved by adding a check to reject lengths above I2C_SMBUS_BLOCK_MAX at both RECV_LEN sites, similar to how i2c-algo-bit handles it.

Defensive priority

High

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 vulnerability status and apply patches as needed
• 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
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The Linux kernel's w1_f19_i2c_master_transfer function does not properly validate the length of I2C block reads, allowing for out-of-bounds reads. The function reads a length byte from the device and uses it to read additional bytes into a buffer without checking if the length is within the buffer's bounds.

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.