Linux Kernel vsock/vmci UAF on peer RST during handshake
CVE-2026-64115 Published on July 19, 2026
vsock/vmci: fix UAF when peer resets connection during handshake
In the Linux kernel, the following vulnerability has been resolved:
vsock/vmci: fix UAF when peer resets connection during handshake
vmci_transport_recv_connecting_server() returned err = 0 for a peer
RST in its default switch arm:
err = pkt->type == VMCI_TRANSPORT_PACKET_TYPE_RST ? 0 : -EINVAL;
That made vmci_transport_recv_listen() skip vsock_remove_pending(),
leaving the pending socket on the listener's pending_links with
sk_state = TCP_CLOSE while destroy: still dropped the explicit
reference taken before schedule_delayed_work().
One second later vsock_pending_work() observed is_pending=true and
performed full cleanup: vsock_remove_pending() then the two trailing
sock_put(sk) calls -- the first reached refcount 0 and __sk_freed
the socket, and the second wrote into the freed object:
BUG: KASAN: slab-use-after-free in refcount_warn_saturate
Write of size 4 at addr ffff88800b1cac80 by task kworker
Workqueue: events vsock_pending_work
Treat peer RST like any other unexpected packet type (err = -EINVAL).
All destroy: arms now return err < 0, so vmci_transport_recv_listen()
removes pending from pending_links synchronously and
vsock_pending_work() takes the is_pending=false / !rejected branch,
dropping only its own work reference. This also closes the
multi-packet race Sashiko reported on v2: pending is removed from
the list before any subsequent packet can find it.
The pre-existing sk_acceptq_removed() gap on the err < 0 path of
vmci_transport_recv_listen() that Sashiko also noted is not
introduced or changed by this patch.
Tested on lts-6.12.79 with KASAN: 52/100 unpatched -> 0/100 patched.
Products Associated with CVE-2026-64115
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Affected Versions
Linux:- Version d021c344051af91f42c5ba9fdedc176740cbd238 and below 1e19f08552b90070ed18bafb1763c78297823af6 is affected.
- Version d021c344051af91f42c5ba9fdedc176740cbd238 and below 1dd531e28f61edd286edc486ab068f135b5ae1eb is affected.
- Version d021c344051af91f42c5ba9fdedc176740cbd238 and below ecda37f8faab3220da199335e42564cb7a9ad145 is affected.
- Version d021c344051af91f42c5ba9fdedc176740cbd238 and below cc27e989a5dfdfcfc1cca7c3be27a0c7532b46cb is affected.
- Version d021c344051af91f42c5ba9fdedc176740cbd238 and below 47e63077605c6c2aa45b3df9847a8cdc1f1f6ef9 is affected.
- Version d021c344051af91f42c5ba9fdedc176740cbd238 and below 440447699c681e26ed58e9c309cad718270a18b4 is affected.
- Version d021c344051af91f42c5ba9fdedc176740cbd238 and below 9fe74e42914c851d68069713b7b917a9c33faf26 is affected.
- Version d021c344051af91f42c5ba9fdedc176740cbd238 and below 99e22ddf4edb63dc8382bc028af928056d3450cf is affected.
- Version 3.9 is affected.
- Before 3.9 is unaffected.
- Version 5.10.258, <= 5.10.* is unaffected.
- Version 5.15.209, <= 5.15.* is unaffected.
- Version 6.1.175, <= 6.1.* is unaffected.
- Version 6.6.142, <= 6.6.* is unaffected.
- Version 6.12.92, <= 6.12.* is unaffected.
- Version 6.18.34, <= 6.18.* is unaffected.
- Version 7.0.11, <= 7.0.* is unaffected.
- Version 7.1, <= * is unaffected.