---
id: CVE-2026-64115
title: 'vsock/vmci: fix UAF when peer resets connection during handshake'
summary: "In the Linux kernel, the following vulnerability has been resolved:\n\nvsock/vmci: fix UAF when peer resets connection during handshake\n\nvmci_transport_recv_connecting_server() returned err = 0 for a peer\nRST in its default switch arm:\n\n\te…"
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= d021c344051af91f42c5ba9fdedc176740cbd238 <
    1e19f08552b90070ed18bafb1763c78297823af6
  - >-
    Linux >= d021c344051af91f42c5ba9fdedc176740cbd238 <
    1dd531e28f61edd286edc486ab068f135b5ae1eb
  - >-
    Linux >= d021c344051af91f42c5ba9fdedc176740cbd238 <
    ecda37f8faab3220da199335e42564cb7a9ad145
  - >-
    Linux >= d021c344051af91f42c5ba9fdedc176740cbd238 <
    cc27e989a5dfdfcfc1cca7c3be27a0c7532b46cb
  - >-
    Linux >= d021c344051af91f42c5ba9fdedc176740cbd238 <
    47e63077605c6c2aa45b3df9847a8cdc1f1f6ef9
  - >-
    Linux >= d021c344051af91f42c5ba9fdedc176740cbd238 <
    440447699c681e26ed58e9c309cad718270a18b4
  - >-
    Linux >= d021c344051af91f42c5ba9fdedc176740cbd238 <
    9fe74e42914c851d68069713b7b917a9c33faf26
  - >-
    Linux >= d021c344051af91f42c5ba9fdedc176740cbd238 <
    99e22ddf4edb63dc8382bc028af928056d3450cf
  - Linux 3.9
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T15:36:34.520586Z'
published: '2026-07-19'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T15:42:23.154Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-64115'
references:
  - url: 'https://git.kernel.org/stable/c/1e19f08552b90070ed18bafb1763c78297823af6'
  - url: 'https://git.kernel.org/stable/c/1dd531e28f61edd286edc486ab068f135b5ae1eb'
  - url: 'https://git.kernel.org/stable/c/ecda37f8faab3220da199335e42564cb7a9ad145'
  - url: 'https://git.kernel.org/stable/c/cc27e989a5dfdfcfc1cca7c3be27a0c7532b46cb'
  - url: 'https://git.kernel.org/stable/c/47e63077605c6c2aa45b3df9847a8cdc1f1f6ef9'
  - url: 'https://git.kernel.org/stable/c/440447699c681e26ed58e9c309cad718270a18b4'
  - url: 'https://git.kernel.org/stable/c/9fe74e42914c851d68069713b7b917a9c33faf26'
  - url: 'https://git.kernel.org/stable/c/99e22ddf4edb63dc8382bc028af928056d3450cf'
tags:
  - cve.org
epss: 0.00135
epssPercentile: 0.02633
ingestedAt: '2026-10-16T17:24:46.805Z'
---

## Overview

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.

## Affected

- `Linux >= d021c344051af91f42c5ba9fdedc176740cbd238 < 1e19f08552b90070ed18bafb1763c78297823af6`
- `Linux >= d021c344051af91f42c5ba9fdedc176740cbd238 < 1dd531e28f61edd286edc486ab068f135b5ae1eb`
- `Linux >= d021c344051af91f42c5ba9fdedc176740cbd238 < ecda37f8faab3220da199335e42564cb7a9ad145`
- `Linux >= d021c344051af91f42c5ba9fdedc176740cbd238 < cc27e989a5dfdfcfc1cca7c3be27a0c7532b46cb`
- `Linux >= d021c344051af91f42c5ba9fdedc176740cbd238 < 47e63077605c6c2aa45b3df9847a8cdc1f1f6ef9`
- `Linux >= d021c344051af91f42c5ba9fdedc176740cbd238 < 440447699c681e26ed58e9c309cad718270a18b4`
- `Linux >= d021c344051af91f42c5ba9fdedc176740cbd238 < 9fe74e42914c851d68069713b7b917a9c33faf26`
- `Linux >= d021c344051af91f42c5ba9fdedc176740cbd238 < 99e22ddf4edb63dc8382bc028af928056d3450cf`
- `Linux 3.9`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.