# CVE-2026-64115: vsock/vmci: fix UAF when peer resets connection during handshake

> A use-after-free vulnerability in the Linux kernel's VMCI transport allows local attackers to execute arbitrary code or escalate privileges via a crafted connection reset.

- **Severity:** High 8.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 19 Jul 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-64115, DEBIAN-CVE-2026-64115, GHSA-c2c8-f8x2-chfh, UBUNTU-CVE-2026-64115

## What is CVE-2026-64115?

CVE-2026-64115 is a high-severity use after free vulnerability in Linux kernel, published on 19 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

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.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2026-64115?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-64115?

Apply the vendor's patch.

## Is CVE-2026-64115 being exploited?

There is no known exploitation of CVE-2026-64115 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-64115 and fix it if it is affected.

What it is: CVE-2026-64115 is a high-severity use after free vulnerability in Linux kernel, published on 19 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-64115 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-64115/ (Markdown: https://insights.sbomify.com/CVE-2026-64115/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-64115
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64115
- OSV: https://osv.dev/vulnerability/CVE-2026-64115

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-64115/
Summaries are generated and may contain mistakes; the official description above is the record.