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Fencer Vulns
medium 5.5

CVE-2026-43285 json

mm/slab: do not access current->mems_allowed_seq if !allow_spin

published 2026-05-08 6 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-28555

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 1%
public exploits
0
none known

Summary

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

mm/slab: do not access current->mems_allowed_seq if !allow_spin

Lockdep complains when get_from_any_partial() is called in an NMI context, because current->mems_allowed_seq is seqcount_spinlock_t and not NMI-safe:

================================ WARNING: inconsistent lock state 6.19.0-rc5-kfree-rcu+ #315 Tainted: G N -------------------------------- inconsistent {INITIAL USE} -> {IN-NMI} usage. kunit_try_catch/9989 [HC1[1]:SC0[0]:HE0:SE1] takes: ffff889085799820 (&____s->seqcount#3){.-.-}-{0:0}, at: ___slab_alloc+0x58f/0xc00 {INITIAL USE} state was registered at: lock_acquire+0x185/0x320 kernel_init_freeable+0x391/0x1150 kernel_init+0x1f/0x220 ret_from_fork+0x736/0x8f0 ret_from_fork_asm+0x1a/0x30 irq event stamp: 56 hardirqs last enabled at (55): [<ffffffff850a68d7>] _raw_spin_unlock_irq+0x27/0x70 hardirqs last disabled at (56): [<ffffffff850858ca>] __schedule+0x2a8a/0x6630 softirqs last enabled at (0): [<ffffffff81536711>] copy_process+0x1dc1/0x6a10 softirqs last disabled at (0): [<0000000000000000>] 0x0

other info that might help us debug this: Possible unsafe locking scenario:

CPU0 ---- lock(&____s->seqcount#3); <Interrupt> lock(&____s->seqcount#3);

*** DEADLOCK ***

According to Documentation/locking/seqlock.rst, seqcount_t is not NMI-safe and seqcount_latch_t should be used when read path can interrupt the write-side critical section. In this case, do not access current->mems_allowed_seq and avoid retry.

Patch / fix

  • Linux Linux 6.18.16, 6.19.6, 7.0
  • linux Debian 14 6.19.6-1

debian advisories DEBIAN-CVE-2026-43285

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-2026-43285 updated

kernel: mm/slab: do not access current->mems_allowed_seq if !allow_spin

  • 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 Red Hat Enterprise Linux 10 kernel
    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

0.12% chance of exploitation in the next 30 days, higher than 1% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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.