# CVE-2026-31469: virtio_net: Fix UAF on dst_ops when IFF_XMIT_DST_RELEASE is cleared and napi_tx is false

> A use-after-free in the Linux virtio_net driver allows attackers to cause a system crash or potentially execute code when specific network configurations are used.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/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:** 22 Apr 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-83264, BELL-CVE-2026-31469, DEBIAN-CVE-2026-31469, GHSA-vggv-f293-vmjw, ROOT-OS-DEBIAN-11-CVE-2026-31469, ROOT-OS-DEBIAN-12-CVE-2026-31469, ROOT-OS-DEBIAN-13-CVE-2026-31469, ROOT-OS-UBUNTU-2204-CVE-2026-31469, ROOT-OS-UBUNTU-2404-CVE-2026-31469, UBUNTU-CVE-2026-31469

## What is CVE-2026-31469?

CVE-2026-31469 is a high-severity use after free vulnerability in Linux kernel, published on 22 Apr 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:

virtio_net: Fix UAF on dst_ops when IFF_XMIT_DST_RELEASE is cleared and napi_tx is false

A UAF issue occurs when the virtio_net driver is configured with napi_tx=N
and the device's IFF_XMIT_DST_RELEASE flag is cleared
(e.g., during the configuration of tc route filter rules).

When IFF_XMIT_DST_RELEASE is removed from the net_device, the network stack
expects the driver to hold the reference to skb->dst until the packet
is fully transmitted and freed. In virtio_net with napi_tx=N,
skbs may remain in the virtio transmit ring for an extended period.

If the network namespace is destroyed while these skbs are still pending,
the corresponding dst_ops structure has freed. When a subsequent packet
is transmitted, free_old_xmit() is triggered to clean up old skbs.
It then calls dst_release() on the skb associated with the stale dst_entry.
Since the dst_ops (referenced by the dst_entry) has already been freed,
a UAF kernel paging request occurs.

fix it by adds skb_dst_drop(skb) in start_xmit to explicitly release
the dst reference before the skb is queued in virtio_net.

Call Trace:
 Unable to handle kernel paging request at virtual address ffff80007e150000
 CPU: 2 UID: 0 PID: 6236 Comm: ping Kdump: loaded Not tainted 7.0.0-rc1+ #6 PREEMPT
  ...
  percpu_counter_add_batch+0x3c/0x158 lib/percpu_counter.c:98 (P)
  dst_release+0xe0/0x110  net/core/dst.c:177
  skb_release_head_state+0xe8/0x108 net/core/skbuff.c:1177
  sk_skb_reason_drop+0x54/0x2d8 net/core/skbuff.c:1255
  dev_kfree_skb_any_reason+0x64/0x78 net/core/dev.c:3469
  napi_consume_skb+0x1c4/0x3a0 net/core/skbuff.c:1527
  __free_old_xmit+0x164/0x230  drivers/net/virtio_net.c:611 [virtio_net]
  free_old_xmit drivers/net/virtio_net.c:1081 [virtio_net]
  start_xmit+0x7c/0x530 drivers/net/virtio_net.c:3329 [virtio_net]
  ...

Reproduction Steps:
NETDEV="enp3s0"

config_qdisc_route_filter() {
    tc qdisc del dev $NETDEV root
    tc qdisc add dev $NETDEV root handle 1: prio
    tc filter add dev $NETDEV parent 1:0 \
	protocol ip prio 100 route to 100 flowid 1:1
    ip route add 192.168.1.100/32 dev $NETDEV realm 100
}

test_ns() {
    ip netns add testns
    ip link set $NETDEV netns testns
    ip netns exec testns ifconfig $NETDEV  10.0.32.46/24
    ip netns exec testns ping -c 1 10.0.32.1
    ip netns del testns
}

config_qdisc_route_filter

test_ns
sleep 2
test_ns

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2026-31469?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-31469?

Apply the vendor's patch.

## Is CVE-2026-31469 being exploited?

There is no known exploitation of CVE-2026-31469 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-2026-31469 and fix it if it is affected.

What it is: CVE-2026-31469 is a high-severity use after free vulnerability in Linux kernel, published on 22 Apr 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-2026-31469 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-2026-31469/ (Markdown: https://insights.sbomify.com/CVE-2026-31469/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-31469
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31469
- OSV: https://osv.dev/vulnerability/CVE-2026-31469

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-31469/
Summaries are generated and may contain mistakes; the official description above is the record.