# CVE-2026-64188: net: qualcomm: rmnet: fix endpoint use-after-free in rmnet_dellink()

> A use-after-free vulnerability in the Linux kernel's Qualcomm rmnet driver allows attackers to cause a system crash or potentially execute code via crafted network packets.

- **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:** 20 Jul 2026
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2026-64188, DEBIAN-CVE-2026-64188, GHSA-6h7j-8h9r-mwrg, ROOT-OS-UBUNTU-2204-CVE-2026-64188, UBUNTU-CVE-2026-64188

## What is CVE-2026-64188?

CVE-2026-64188 is a high-severity use after free vulnerability in Linux kernel, published on 20 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:

net: qualcomm: rmnet: fix endpoint use-after-free in rmnet_dellink()

rmnet_dellink() removes the endpoint from the hash table with
hlist_del_init_rcu() and then immediately frees it with kfree(). However,
RCU readers on the receive path (rmnet_rx_handler ->
__rmnet_map_ingress_handler) may still hold a reference to the endpoint and
dereference ep->egress_dev after the memory has been freed. The endpoint is
a kmalloc-32 object, and the stale read at offset 8 corresponds to the
egress_dev pointer.

  BUG: unable to handle page fault for address: ffffffffde942eef
  Oops: 0002 [#1] SMP NOPTI
  CPU: 1 UID: 0 PID: 137 Comm: poc_write Not tainted 7.0.0+ #4 PREEMPTLAZY
  RIP: 0010:rmnet_vnd_rx_fixup (rmnet_vnd.c:27)
  Call Trace:
   <TASK>
   __rmnet_map_ingress_handler (rmnet_handlers.c:48 rmnet_handlers.c:101)
   rmnet_rx_handler (rmnet_handlers.c:129 rmnet_handlers.c:235)
   __netif_receive_skb_core.constprop.0 (net/core/dev.c:6096)
   __netif_receive_skb_one_core (net/core/dev.c:6208)
   netif_receive_skb (net/core/dev.c:6467)
   tun_get_user (drivers/net/tun.c:1955)
   tun_chr_write_iter (drivers/net/tun.c:2003)
   vfs_write (fs/read_write.c:688)
   ksys_write (fs/read_write.c:740)
   </TASK>

Add an rcu_head field to struct rmnet_endpoint and replace kfree() with
kfree_rcu() so the endpoint memory remains valid through the RCU grace
period. Also remove the rmnet_vnd_dellink() call and inline only the
nr_rmnet_devs decrement, since rmnet_vnd_dellink() would set
ep->egress_dev to NULL during the grace period, creating a data race
with lockless readers.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2026-64188?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-64188?

Apply the vendor's patch.

## Is CVE-2026-64188 being exploited?

There is no known exploitation of CVE-2026-64188 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-2026-64188 and fix it if it is affected.

What it is: CVE-2026-64188 is a high-severity use after free vulnerability in Linux kernel, published on 20 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-2026-64188 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-2026-64188/ (Markdown: https://insights.sbomify.com/CVE-2026-64188/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-64188
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64188
- OSV: https://osv.dev/vulnerability/CVE-2026-64188

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-64188/
Summaries are generated and may contain mistakes; the official description above is the record.