CVE-2026-74300 Linux CVE debrief

Who should care

Linux kernel developers and maintainers, Bluetooth HCI implementers, and users of Linux-based systems with Bluetooth capabilities should assess exposure and verify the Linux kernel version.

Why it matters

This vulnerability in the Linux kernel's Bluetooth HCI implementation can lead to a buffer overflow, potentially allowing an attacker to execute arbitrary code. Linux kernel developers and maintainers, Bluetooth HCI implementers, and users of Linux-based systems with Bluetooth capabilities should assess exposure and verify the Linux kernel version.

• Verify Linux kernel version and apply updates if necessary to prevent potential buffer overflows
• Monitor Bluetooth HCI responses for potential buffer overflows
• Review and apply patches from the Linux kernel maintainers

Technical summary

The Linux kernel's Bluetooth HCI implementation does not properly validate the length of codec capability elements, leading to a potential buffer overflow when copying data from the response payload. This vulnerability can be exploited by a malformed controller response. The HCI layer should validate the full element size, including the length byte, before adding it to the accumulated capability length. This preserves all well-formed capability elements and drops only truncated controller responses. Affected product deployments should be reviewed and updated to prevent potential buffer overflows.

Defensive priority

High

Recommended defensive actions

• Review and apply patches from the Linux kernel maintainers
• Verify the Linux kernel version and apply updates if necessary
• Monitor Bluetooth HCI responses for potential buffer overflows
• 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
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance

Evidence notes

The CVE Program record and NVD vulnerability detail provide information on the vulnerability, including its description, CVSS score, and affected versions. The Linux kernel's Bluetooth HCI implementation is vulnerable to a buffer overflow due to improper validation of codec capability elements.

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.