CVE-2026-64115

High

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.

Package Linux Kernel
Published 2026-07-19
Last modified 2026-08-12
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

8.8

out of 10
High
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Weakness type

CWE-416

CVE-2026-64115 is a Use After Free vulnerability

What is Use After Free?

The product references memory after it has been freed, which may cause it to crash, use unexpected values, or execute code. Learn more on MITRE CWE

Affected versions

Linux kernel versions 3.9 and later are affected. Fixed in 5.10.258, 5.15.209, 6.1.175, 6.6.142, 6.12.92, 6.18.34, 7.0.11, 7.1 and their respective stable series.

Affected from
≥ 3.9
Fixed in
✓ 5.10.258 5.10.x ✓ 5.15.209 5.15.x ✓ 6.1.175 6.1.x ✓ 6.6.142 6.6.x ✓ 6.12.92 6.12.x ✓ 6.18.34 6.18.x ✓ 7.0.11 7.0.x ✓ 7.1

Frequently asked questions

  • What is CVE-2026-64115?

    CVE-2026-64115 is a High severity Linux kernel vulnerability with a CVSS score of 8.8 out of 10 , classified as an Use After Free flaw (CWE-416) . It affects Linux kernel versions from 3.9 onward and has been patched in 5.10.258, 5.15.209, 6.1.175 and others. CVE-2026-64115 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2026-64115?

    CVE-2026-64115 has a CVSS score of 8.8 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H .

  • Is there a patch available for CVE-2026-64115?

    Yes. CVE-2026-64115 has been patched. Fixed versions include 5.10.258, 5.15.209, 6.1.175 and others. If you are running Linux kernel 3.9 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2026-64115 actively exploited?

    No. CVE-2026-64115 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.