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Fencer Vulns
high 7.8

CVE-2026-31406 json

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

published 2026-04-06 7 mo ago modified 2026-08-05 3 mo ago also EUVD-2026-19198

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 5%
public exploits
0
none known

Summary

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().

Patch / fix

  • Linux Linux 6.12.80, 6.18.21, 6.19.11, 7.0
  • linux Debian 13 6.12.85-1
  • linux Debian 14 6.19.11-1

debian advisories DEBIAN-CVE-2026-31406

  • kernel-livepatch-SLE16_Update_10 SLES for SAP applications 16.0, SLES 16.0 2-160000.1.1
  • kernel-livepatch-SLE16_Update_11 SLES for SAP applications 16.0, SLES 16.0 2-160000.1.1
  • kernel-livepatch-SLE16_Update_8 SLES for SAP applications 16.0, SLES 16.0 3-160000.1.1
  • kernel-livepatch-SLE16_Update_9 SLES for SAP applications 16.0, SLES 16.0 2-160000.1.1
  • kernel-syms Linux Micro Extras 6.2 6.12.0-160000.33.1
  • kernel-obs-build Linux Micro Extras 6.2 6.12.0-160000.33.1

suse advisories SUSE-SU-2026:22037-1SUSE-SU-2026:22036-1SUSE-SU-2026:22034-1SUSE-SU-2026:22029-1SUSE-SU-2026:21834-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-31406 updated cvss 5.5

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

  • Red Hat Enterprise Linux 10 kernel
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.16% chance of exploitation in the next 30 days, higher than 5% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.