xfrm: Fix work re-schedule after cancel in xfrm_nat_keepalive_net_fini()_CVE-2026-31406

7.8 / 10

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Description

In the Linux kernel, the following vulnerability has been resolved:

xfrm: Fix work re-schedule after cancel in xfrm_nat_keepalive_net_fini()

After cancel_delayed_work_sync() is called from
xfrm_nat_keepalive_net_fini(), xfrm_state_fini() flushes remaining
states via __xfrm_state_delete(), which calls
xfrm_nat_keepalive_state_updated() to re-schedule nat_keepalive_work.

The following is a simple race scenario:

cpu0 cpu1

cleanup_net() [Round 1]
ops_undo_list()
xfrm_net_exit()
xfrm_nat_keepalive_net_fini()
cancel_delayed_work_sync(nat_keepalive_work);
xfrm_state_fini()
xfrm_state_flush()
xfrm_state_delete(x)
__xfrm_state_delete(x)
xfrm_nat_keepalive_state_updated(x)
schedule_delayed_work(nat_keepalive_work);
rcu_barrier();
net_complete_free();
net_passive_dec(net);
llist_add(&net->defer_free_list, &defer_free_list);

cleanup_net() [Round 2]
rcu_barrier();
net_complete_free()
kmem_cache_free(net_cachep, net);
nat_keepalive_work()
// on freed net

To prevent this, cancel_delayed_work_sync() is replaced with
disable_delayed_work_sync().

Basic Information

ID CVE-2026-31406

Source Linux

Published Apr 6, 2026 at 07:38

Modified Apr 27, 2026 at 14:02

Affected Product

Vendor Linux

Product Linux

Version f531d13bdfe3f4f084aaa8acae2cb0f02295f5ae

Affected Versions Linux Linux f531d13bdfe3f4f084aaa8acae2cb0f02295f5ae
Linux Linux f531d13bdfe3f4f084aaa8acae2cb0f02295f5ae
Linux Linux f531d13bdfe3f4f084aaa8acae2cb0f02295f5ae
Linux Linux f531d13bdfe3f4f084aaa8acae2cb0f02295f5ae
Linux Linux 6.11

References

{
    "lastseen": "",
    "description": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: Fix work re-schedule after cancel in xfrm_nat_keepalive_net_fini()\n\nAfter cancel_delayed_work_sync() is called from\nxfrm_nat_keepalive_net_fini(), xfrm_state_fini() flushes remaining\nstates via __xfrm_state_delete(), which calls\nxfrm_nat_keepalive_state_updated() to re-schedule nat_keepalive_work.\n\nThe following is a simple race scenario:\n\n           cpu0                             cpu1\n\ncleanup_net() [Round 1]\n  ops_undo_list()\n    xfrm_net_exit()\n      xfrm_nat_keepalive_net_fini()\n        cancel_delayed_work_sync(nat_keepalive_work);\n      xfrm_state_fini()\n        xfrm_state_flush()\n          xfrm_state_delete(x)\n            __xfrm_state_delete(x)\n              xfrm_nat_keepalive_state_updated(x)\n                schedule_delayed_work(nat_keepalive_work);\n  rcu_barrier();\n  net_complete_free();\n  net_passive_dec(net);\n    llist_add(&net->defer_free_list, &defer_free_list);\n\ncleanup_net() [Round 2]\n  rcu_barrier();\n  net_complete_free()\n    kmem_cache_free(net_cachep, net);\n                                     nat_keepalive_work()\n                                       // on freed net\n\nTo prevent this, cancel_delayed_work_sync() is replaced with\ndisable_delayed_work_sync().",
    "published": "2026-04-06T07:38:18.840Z",
    "modified": "2026-04-27T14:02:53.636Z",
    "type": "cve",
    "title": "xfrm: Fix work re-schedule after cancel in xfrm_nat_keepalive_net_fini()",
    "source": "Linux",
    "references": "https://git.kernel.org/stable/c/32d0f44c2f14d60fe8e920e69a28c11051543ec1\nhttps://git.kernel.org/stable/c/2255ed6adbc3100d2c4a83abd9d0396d04b87792\nhttps://git.kernel.org/stable/c/21f2fc49ca6faa393c31da33b8a4e6c41fc84c13\nhttps://git.kernel.org/stable/c/daf8e3b253aa760ff9e96c7768a464bc1d6b3c90",
    "id": "CVE-2026-31406",
    "bulletinFamily": "",
    "cwe": null,
    "cvelist": null,
    "sourceData": "Linux Linux f531d13bdfe3f4f084aaa8acae2cb0f02295f5ae\nLinux Linux f531d13bdfe3f4f084aaa8acae2cb0f02295f5ae\nLinux Linux f531d13bdfe3f4f084aaa8acae2cb0f02295f5ae\nLinux Linux f531d13bdfe3f4f084aaa8acae2cb0f02295f5ae\nLinux Linux 6.11",
    "sourceHref": "",
    "cvss": {
        "score": 7.8,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "Linux",
    "version": "f531d13bdfe3f4f084aaa8acae2cb0f02295f5ae",
    "vendor": "Linux",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}

Description

Basic Information

Affected Product

References

💭 Join the Security Discussion ❌ Cancel Reply