CVE-2026-98459 Linux CVE debrief

Who should care

Linux kernel developers and maintainers, Bluetooth ISO implementers, Linux system administrators, and security teams responsible for vulnerability management and patching. These stakeholders should review and apply the patch, verify the Linux kernel version, and monitor system logs for potential exploitation attempts. Additionally, operators and platform administrators may need to be informed about the vulnerability and its potential impact on their

Why it matters

A vulnerability in the Linux kernel's Bluetooth ISO implementation has been addressed. The issue involves an imbalance in the parent hold in the `hci_bind_bis()` function, which could lead to a potential use-after-free vulnerability. Linux kernel developers and maintainers, Bluetooth ISO implementers, and Linux system administrators should review and apply the patch, verify the Linux kernel version, and monitor system logs for potential exploitation attempts.

• Verify Linux kernel version and apply patch if necessary
• Monitor system logs for potential exploitation attempts
• Review and update Bluetooth ISO implementation

Technical summary

The vulnerability is caused by an imbalance in the parent hold in the `hci_bind_bis()` function. The `hci_conn_link()` function takes a lifetime reference to its parent with `hci_conn_get()`, but only takes an operational hold on the child. The `hci_conn_unlink()` function later balances both a hold and a reference on the parent. However, when an additional BIS is added, `hci_bind_bis()` obtains the parent from `hci_conn_hash_lookup_big()`, which returns a bare pointer. This can lead to the parent being scheduled for disconnection while its socket is still in use.

Defensive priority

Medium

Recommended defensive actions

• Review and apply the patch to the Linux kernel
• Verify the Linux kernel version and apply the patch 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 the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• Check relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The vulnerability was introduced in the Linux kernel's Bluetooth ISO implementation. The issue arises from an imbalance in the parent hold in the `hci_bind_bis()` function. The `hci_conn_link()` function takes a lifetime reference to its parent with `hci_conn_get()`, but only takes an operational hold on the child. The `hci_conn_unlink()` function later balances both a hold and a reference on the parent. However, when an additional BIS is added, `hci_bind_bis()` obtains the parent from `hci_conn_hash_lookup_big()`, which returns a bare pointer. This can lead to the parent being scheduled for disconnection while its socket is still in use.

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.