# CVE-2026-64189: netfilter: ipset: fix race between dump and ip_set_list resize

> A race condition in the Linux kernel netfilter ipset module allows a use-after-free, potentially leading to system crashes or arbitrary code execution.

- **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:** 19 Oct 2026
- **Also known as:** AZL-92868, BELL-CVE-2026-64189, DEBIAN-CVE-2026-64189, GHSA-38c9-7h78-x2jx, ROOT-OS-DEBIAN-11-CVE-2026-64189, ROOT-OS-DEBIAN-12-CVE-2026-64189, ROOT-OS-UBUNTU-2204-CVE-2026-64189, UBUNTU-CVE-2026-64189

## What is CVE-2026-64189?

CVE-2026-64189 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:

netfilter: ipset: fix race between dump and ip_set_list resize

The release path of ip_set_dump_do() and ip_set_dump_done() read
inst->ip_set_list via ip_set_ref_netlink(), a plain rcu_dereference_raw()
of the array pointer. These run from netlink_recvmsg() without the nfnl
mutex and without an RCU read-side critical section.

A concurrent ip_set_create() can grow the array: it publishes the new
array, calls synchronize_net() and then kvfree()s the old one. Since the
dump paths read the array outside any RCU reader, synchronize_net() does
not wait for them and the old array can be freed while they still index
into it, causing a use-after-free.

The dumped set itself stays pinned via set->ref_netlink, so only the
array load needs protecting. Take rcu_read_lock() around it, matching
ip_set_get_byname() and __ip_set_put_byindex().

  BUG: KASAN: slab-use-after-free in ip_set_dump_do (net/netfilter/ipset/ip_set_core.c:1697)
  Read of size 8 at addr ffff88800b5c4018 by task exploit/150
  Call Trace:
   ...
   kasan_report (mm/kasan/report.c:595)
   ip_set_dump_do (net/netfilter/ipset/ip_set_core.c:1697)
   netlink_dump (net/netlink/af_netlink.c:2325)
   netlink_recvmsg (net/netlink/af_netlink.c:1976)
   sock_recvmsg (net/socket.c:1159)
   __sys_recvfrom (net/socket.c:2315)
   ...
  Oops: general protection fault, probably for non-canonical address ... KASAN NOPTI
  KASAN: maybe wild-memory-access in range [0x02d6...d0-0x02d6...d7]
  RIP: 0010:ip_set_dump_do (net/netfilter/ipset/ip_set_core.c:1698)
  Kernel panic - not syncing: Fatal exception

Weakness: CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization)

## Which versions are affected by CVE-2026-64189?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-64189?

Apply the vendor's patch.

## Is CVE-2026-64189 being exploited?

There is no known exploitation of CVE-2026-64189 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-2026-64189 and fix it if it is affected.

What it is: CVE-2026-64189 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-2026-64189 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-2026-64189/ (Markdown: https://insights.sbomify.com/CVE-2026-64189/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-64189
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64189
- OSV: https://osv.dev/vulnerability/CVE-2026-64189

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-64189/
Summaries are generated and may contain mistakes; the official description above is the record.