CVE-2026-63914
Received Received - Intake

XFRM Migrate Notification Routing in Linux Kernel

Publication date: 2026-07-19

Last updated on: 2026-07-19

Assigner: kernel.org

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.

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Meta Information

Published
2026-07-19
Last Modified
2026-07-19
Generated
2026-07-20
AI Q&A
2026-07-19
EPSS Evaluated
N/A
NVD
CVE-2026-63914
EUVD
EUVD-2026-45687

Affected Vendors & Products

Showing 2 associated CPEs
Vendor Product Version / Range
linux_kernel linux_kernel *
linux linux_kernel *

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves incorrect routing of XFRM_MSG_MIGRATE notifications. The issue occurs because two functions, xfrm_send_migrate() and pfkey_send_migrate(), hardcode the initial network namespace (&init_net) when sending multicast notifications. This causes notifications to be sent to the wrong network namespace, breaking IKE daemon functionality in non-init namespaces and exposing init_net listeners to unrelated migration events.

Detection Guidance

This vulnerability involves incorrect network namespace handling in the Linux kernel's XFRM subsystem. Detection requires checking kernel logs for XFRM migration events and verifying if IKE daemons receive proper notifications. Monitor for errors in xfrm_user.c and af_key.c related to netlink multicast groups. Check if IKE daemons in non-init netns fail to receive migration notifications.

Impact Analysis

If you use Linux network namespaces with IKE daemons (like those for VPNs), this vulnerability could break address updates in non-init namespaces. IKEv2 MOBIKE functionality may fail silently, causing connectivity issues. Systems relying on network namespace isolation could also see unintended exposure of migration events to init_net listeners.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards. It involves a Linux kernel networking issue where XFRM migration notifications are incorrectly routed to the init_net namespace instead of the caller's namespace. This could lead to misconfigured network security policies or failed address updates in IKEv2 MOBIKE, potentially impacting secure communications but not explicitly violating compliance requirements.

Mitigation Strategies

Apply the latest Linux kernel patches addressing this issue. Update IKE daemons to handle netns-aware migration events. Monitor network traffic for unexpected XFRM_MSG_MIGRATE messages. Restrict access to NETLINK_XFRM sockets to prevent unauthorized migration events.

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