# CVE-2026-63914: xfrm: route MIGRATE notifications to caller's netns

> Linux kernel XFRM migration notifications leak to init_net, exposing network details to unauthorized listeners and breaking netns isolation.

- **Severity:** High 7.3 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:L`)
- **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:** 19 Jul 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-63914, DEBIAN-CVE-2026-63914, GHSA-xcfp-8r3c-9qrj, ROOT-OS-UBUNTU-2204-CVE-2026-63914, UBUNTU-CVE-2026-63914

## What is CVE-2026-63914?

CVE-2026-63914 is a high-severity vulnerability in Linux, published on 19 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:

xfrm: route MIGRATE notifications to caller's netns

xfrm_send_migrate() in net/xfrm/xfrm_user.c and pfkey_send_migrate()
in net/key/af_key.c both hardcode &init_net for the multicast that
announces a successful XFRM_MSG_MIGRATE / SADB_X_MIGRATE.

XFRM_MSG_MIGRATE arrives on a per-netns NETLINK_XFRM socket, and the
rest of the xfrm/af_key netlink path was made netns-aware in 2008.
The other 14 multicast paths in xfrm_user.c route their event using
xs_net(x), xp_net(xp) or sock_net(skb->sk); only the migrate path
was missed.

Two consequences of the init_net hardcoding:

  1. The notification (selector, old/new endpoint addresses, and the
     km_address) is delivered to listeners on init_net's
     XFRMNLGRP_MIGRATE / pfkey BROADCAST_ALL groups rather than on
     the issuing netns. An IKE daemon running in init_net therefore
     receives migration notifications originating from any other
     netns on the host.

  2. An IKE daemon running inside a non-init netns and subscribed
     to its own XFRMNLGRP_MIGRATE / pfkey groups never receives the
     notification of its own migration. IKEv2 MOBIKE / address-update
     handling inside a netns is silently broken.

Thread struct net through km_migrate() and the xfrm_mgr.migrate
function pointer, drop the &init_net override in xfrm_send_migrate()
and pfkey_send_migrate(), and pass the caller's net (already in
scope in xfrm_migrate() via sock_net(skb->sk)) all the way down.
struct xfrm_mgr is in-tree only and not exported as a stable API,
so the function-pointer signature change is internal.

pfkey_broadcast() is already netns-aware via net_generic(net,
pfkey_net_id) since the pernet conversion. The five other
pfkey_broadcast() callers in af_key.c already pass xs_net(x),
sock_net(sk) or a per-netns net, so this only removes the
&init_net outlier.

Weakness: CWE-862 (Missing Authorization)

## Which versions are affected by CVE-2026-63914?


## How do I fix CVE-2026-63914?

Apply the vendor's patch.

## Is CVE-2026-63914 being exploited?

There is no known exploitation of CVE-2026-63914 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-63914 and fix it if it is affected.

What it is: CVE-2026-63914 is a high-severity vulnerability in Linux, published on 19 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-2026-63914 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-2026-63914/ (Markdown: https://insights.sbomify.com/CVE-2026-63914/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-63914
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-63914
- OSV: https://osv.dev/vulnerability/CVE-2026-63914

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-63914/
Summaries are generated and may contain mistakes; the official description above is the record.