CVE-2026-63946 (CVSS 8.8)

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.

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CVSS v3.1 Score

8.8

HIGH

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0033

Probability of exploitation

0.25%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

References

Other References

https://git.kernel.org/stable/c/119fb6f80c44dc1c65d604cf28e64c56bd9b6568 https://git.kernel.org/stable/c/1a6b803b00ccdd7666506adbe01ddae1c72d1ca9 https://git.kernel.org/stable/c/47f23a259517abbdb8032c057a1e8a6bf3734878 https://git.kernel.org/stable/c/b04ec131325baf4ea4577d6c6e6b86cf092e3731 https://git.kernel.org/stable/c/c318aa51830a3d2cc1229968fe521441c97356cd https://git.kernel.org/stable/c/c57ea90f203c8b8b41a474f19a09000d0f841436

Frequently Asked Questions

What is CVE-2026-63946? +

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. It has a CVSS v3.1 base score of 8.8 (HIGH).

How severe is CVE-2026-63946? +

CVE-2026-63946 has a CVSS v3.1 score of 8.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0033, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-63946? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

CVE-2026-63946