CVE-2026-52947

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> net: qrtr: fix refcount saturation and potential UAF in qrtr_port_remove<br /> <br /> In qrtr_port_remove(), the socket reference count is decremented via<br /> __sock_put() before the port is removed from the qrtr_ports XArray and<br /> before the RCU grace period elapses.<br /> <br /> This breaks the fundamental RCU update paradigm. It exposes a race<br /> window where a concurrent RCU reader (such as qrtr_reset_ports() or<br /> qrtr_port_lookup()) can obtain a pointer to the socket from the XArray,<br /> and attempt to call sock_hold() on a socket whose reference count has<br /> already dropped to zero.<br /> <br /> This exact race condition was hit during syzkaller fuzzing, leading to<br /> the following refcount saturation warning and a potential Use-After-Free:<br /> <br /> refcount_t: saturated; leaking memory.<br /> WARNING: CPU: 3 PID: 1273 at lib/refcount.c:22 refcount_warn_saturate+0xae/0x1d0<br /> Modules linked in: qrtr(+) bochs drm_shmem_helper ...<br /> Call Trace:<br /> <br /> qrtr_reset_ports net/qrtr/af_qrtr.c:768 [inline] [qrtr]<br /> __qrtr_bind.isra.0+0x48b/0x570 net/qrtr/af_qrtr.c:805 [qrtr]<br /> qrtr_bind+0x17d/0x210 net/qrtr/af_qrtr.c:901 [qrtr]<br /> kernel_bind+0xe4/0x120 net/socket.c:3592<br /> qrtr_ns_init+0x1a6/0x380 net/qrtr/ns.c:715 [qrtr]<br /> qrtr_proto_init+0x3b/0xff0 net/qrtr/af_qrtr.c:169 [qrtr]<br /> do_one_initcall+0xf5/0x5e0 init/main.c:1283<br /> ...<br /> <br /> <br /> Fix this by deferring the reference count decrement until after the<br /> xa_erase() and the synchronize_rcu() complete.<br /> <br /> (Note: The v1 of this patch incorrectly replaced __sock_put() with<br /> sock_put(). As Simon Horman pointed out, the callers of qrtr_port_remove()<br /> still hold a reference to the socket, so freeing the socket memory here<br /> would lead to a subsequent UAF in the caller. Thus, the __sock_put() is<br /> kept, but only repositioned to close the RCU race.)