Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: ISO: fix use-after-free of listener socket in iso_conn_ready iso_conn_ready() looks up the BIS listener socket with iso_get_sock(), which takes a reference, and then, without re-checking its state, creates a child socket from it: parent = iso_get_sock(hdev, ...); if (!parent) return; lock_sock(parent); sk = iso_sock_alloc(sock_net(parent), NULL, BTPROTO_ISO, ...); ... iso_chan_add(conn, sk, parent); ... release_sock(parent); sock_put(parent); If the listener socket is closed concurrently, between iso_get_sock() and lock_sock(), the reference taken by iso_get_sock() may be the last one: the close path drops the link-list reference, and once iso_conn_ready() drops its own reference at the end of the function the socket is freed. The child socket, however, is already linked to the freed parent, and a later disconnect of the child runs iso_chan_del() -> bt_accept_unlink(), which dereferences the dangling parent pointer into the freed accept queue (a use-after-free). The same dangling pointer is also dereferenced through parent->***() in iso_chan_del(). Fix it the same way the connected (non-BIS) path was fixed in commit 0d255e63fcf3 ("Bluetooth: ISO: hold sk properly in iso_conn_ready"): after taking the socket lock, re-check that the parent is still a listening, alive socket, and bail out otherwise.

Predictions

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

https://git.kernel.org/linus/560bef609fa5992745929e8d7d458b9d88dd2830 (7.3-rc1)

https://git.kernel.org/linus/560bef609fa5992745929e8d7d458b9d88dd2830 (7.3-rc1)

References

• https://git.kernel.org/stable/c/03288b7447c9e572f8ab82fc29cfb4ca719ab210
• https://git.kernel.org/stable/c/2387cd06a2c0b416f05028b02bba1089f54c28d9
• https://git.kernel.org/stable/c/49fd7116f76b860b230843700fb7423ab5331e1f
• https://git.kernel.org/stable/c/560bef609fa5992745929e8d7d458b9d88dd2830
• https://security-tracker.debian.org/tracker/CVE-2026-80914