CVE-2026-63946: Bluetooth: ISO: fix UAF in iso_recv_frame

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-19 · updated 2026-10-28
Weakness: CWE-362

Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: ISO: fix UAF in iso_recv_frame iso_recv_frame reads conn->sk under iso_conn_lock but releases the lock before using sk, with no reference held. A concurrent iso_sock_kill() can free sk in that window, causing use-after-free on sk->sk_state and sock_queue_rcv_skb(). Fix by replacing the bare pointer read with iso_sock_hold(conn), which calls sock_hold() while the spinlock is held, atomically elevating the refcount before the lock drops. Add a drop_put label so sock_put() is called on all exit paths where the hold succeeded.

Affected products

Linux kernel: from 6.0 before 6.1.176; from 6.2 before 6.6.143; from 6.7 before 6.12.93; from 6.13 before 6.18.35; from 6.19 before 7.0.12; 7.1-rc1, 7.1-rc2, 7.1-rc3, 7.1-rc4, 7.1-rc5 — fixed in 6.1.176, 6.6.143, 6.12.93, 6.18.35, 7.0.12
Linux kernel: 6.0 — fixed in 7.1

How to fix

Upgrade to a fixed version: Linux kernel 6.1.176, 6.6.143, 6.12.93, 6.18.35; Linux kernel 7.1. Check the vendor advisory for mitigations.

References

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