CVE-2026-46029

mm/slab: return NULL early from kmalloc_nolock() in NMI on UP

Published May 27, 2026 CVSS 3.1 · 7 High EPSS < 1% KEV · Not listed
Description
In the Linux kernel, the following vulnerability has been resolved:

mm/slab: return NULL early from kmalloc_nolock() in NMI on UP

On UP kernels (!CONFIG_SMP), spin_trylock() is a no-op that
unconditionally succeeds even when the lock is already held. As a
result, kmalloc_nolock() called from NMI context can re-enter the slab
allocator and acquire n->list_lock that the interrupted context is
already holding, corrupting slab state.

With CONFIG_DEBUG_SPINLOCK on UP, the following BUG is triggered with
the slub_kunit test module:

BUG: spinlock trylock failure on UP on CPU#0, kunit_try_catch/243
[...]
Call Trace:
<NMI>
dump_stack_lvl+0x3f/0x60
do_raw_spin_trylock+0x41/0x50
_raw_spin_trylock+0x24/0x50
get_from_partial_node+0x120/0x4d0
___slab_alloc+0x8a/0x4c0
kmalloc_nolock_noprof+0x164/0x310
[...]
</NMI>

Fix this by returning NULL early when invoked from NMI on a UP kernel.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Ubuntu USN Ubuntu USN USN-8488-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8489-1 Linux kernel (OEM) vulnerabilities
Ubuntu USN Ubuntu USN USN-8488-2 Linux kernel (Raspberry Pi) vulnerabilities
Ubuntu USN Ubuntu USN USN-8507-1 Linux kernel (NVIDIA) vulnerabilities
Ubuntu USN Ubuntu USN USN-8569-1 Linux kernel (HWE) vulnerabilities
Ubuntu USN Ubuntu USN USN-8603-1 Linux kernel (Azure) vulnerabilities
History
Type Values Removed Values Added
Weaknesses NVD-CWE-noinfo
CPEs cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*
Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

Type Values Removed Values Added
Weaknesses CWE-250
CWE-362
CWE-416
Type Values Removed Values Added
Weaknesses CWE-250
CWE-362
CWE-416
Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: mm/slab: return NULL early from kmalloc_nolock() in NMI on UP On UP kernels (!CONFIG_SMP), spin_trylock() is a no-op that unconditionally succeeds even when the lock is already held. As a result, kmalloc_nolock() called from NMI context can re-enter the slab allocator and acquire n->list_lock that the interrupted context is already holding, corrupting slab state. With CONFIG_DEBUG_SPINLOCK on UP, the following BUG is triggered with the slub_kunit test module: BUG: spinlock trylock failure on UP on CPU#0, kunit_try_catch/243 [...] Call Trace: <NMI> dump_stack_lvl+0x3f/0x60 do_raw_spin_trylock+0x41/0x50 _raw_spin_trylock+0x24/0x50 get_from_partial_node+0x120/0x4d0 ___slab_alloc+0x8a/0x4c0 kmalloc_nolock_noprof+0x164/0x310 [...] </NMI> Fix this by returning NULL early when invoked from NMI on a UP kernel.
Title mm/slab: return NULL early from kmalloc_nolock() in NMI on UP
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Aug 5, 2026, 12:29 PM
Reserved
May 13, 2026, 3:03 PM
Status
Analyzed
Published
May 27, 2026, 2:17 PM
Modified
Jun 17, 2026, 10:52 AM
Severity
Public date
May 27, 2026, 12:00 AM