# CVE-2026-64569: mpls: fix NULL deref in mpls_valid_fib_dump_req() on CONFIG_INET=n

> An unprivileged local user can cause a kernel crash via a NULL pointer dereference in MPLS route dumping when IPv4 support is disabled.

- **Severity:** Not scored
- **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:** 5 Aug 2026
- **Updated:** 19 Aug 2026
- **Also known as:** AZL-94479, BELL-CVE-2026-64569, DEBIAN-CVE-2026-64569, GHSA-4gx4-c274-rxvr, UBUNTU-CVE-2026-64569

## What is CVE-2026-64569?

CVE-2026-64569 is a vulnerability in Linux, published on 5 Aug 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:

mpls: fix NULL deref in mpls_valid_fib_dump_req() on CONFIG_INET=n

On CONFIG_INET=n builds, mpls_valid_fib_dump_req() walks the parsed
attribute table itself instead of calling ip_valid_fib_dump_req(). The
RTA_OIF arm passes tb[RTA_OIF] to nla_get_u32() without checking it is
present, so an RTM_GETROUTE dump for AF_MPLS with strict checking and no
RTA_OIF hits a NULL dereference.

RTM_GETROUTE is RTNL_KIND_GET, which rtnetlink_rcv_msg() permits without
CAP_NET_ADMIN, so an unprivileged user can trigger it.

  Oops: general protection fault, probably for non-canonical address
        0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI
  KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
  RIP: 0010:mpls_valid_fib_dump_req (net/mpls/af_mpls.c:2189)
  Call Trace:
   mpls_dump_routes (net/mpls/af_mpls.c:2236)
   netlink_dump (net/netlink/af_netlink.c:2331)
   __netlink_dump_start (net/netlink/af_netlink.c:2446)
   rtnetlink_rcv_msg (net/core/rtnetlink.c:7033)
   netlink_rcv_skb (net/netlink/af_netlink.c:2556)
   netlink_unicast (net/netlink/af_netlink.c:1345)
   netlink_sendmsg (net/netlink/af_netlink.c:1900)
   __sock_sendmsg (net/socket.c:790)
   ____sys_sendmsg (net/socket.c:2684)
   ___sys_sendmsg (net/socket.c:2738)
   __sys_sendmsg (net/socket.c:2770)
   do_syscall_64 (arch/x86/entry/syscall_64.c:94)
   entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)

Skip unset attributes, as ip_valid_fib_dump_req() does.

## Which versions are affected by CVE-2026-64569?


## How do I fix CVE-2026-64569?

Apply the vendor's patch.

## Is CVE-2026-64569 being exploited?

There is no known exploitation of CVE-2026-64569 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-64569 and fix it if it is affected.

What it is: CVE-2026-64569 is a vulnerability in Linux, published on 5 Aug 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-2026-64569 in the wild and no public exploit code.

Affected product: Linux. 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-2026-64569/ (Markdown: https://insights.sbomify.com/CVE-2026-64569/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-64569
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64569
- OSV: https://osv.dev/vulnerability/CVE-2026-64569

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-64569/
Summaries are generated and may contain mistakes; the official description above is the record.