CVE-2026-46029 (GCVE-0-2026-46029)

Vulnerability from cvelistv5 – Published: 2026-05-27 12:56 – Updated: 2026-08-05 12:29
VLAI
Title
mm/slab: return NULL early from kmalloc_nolock() in NMI on UP
Summary
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.
Severity
7 (High)
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: af92793e52c3a99b828ed4bdd277fd3e11c18d08 , < a8d95d274be241ad21f6523bf2d6ba0d7d7e46b7 (git)
Affected: af92793e52c3a99b828ed4bdd277fd3e11c18d08 , < d66553204a15bdb257d9ef8aca1e12f5fbb910b2 (git)
Affected: af92793e52c3a99b828ed4bdd277fd3e11c18d08 , < 5b31044e649e3e54c2caef135c09b371c2fbcd08 (git)
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Linux Linux Affected: 6.18
Unaffected: 0 , < 6.18 (semver)
Unaffected: 6.18.27 , ≤ 6.18.* (semver)
Unaffected: 7.0.4 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
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{
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/slab: return NULL early from kmalloc_nolock() in NMI on UP\n\nOn UP kernels (!CONFIG_SMP), spin_trylock() is a no-op that\nunconditionally succeeds even when the lock is already held. As a\nresult, kmalloc_nolock() called from NMI context can re-enter the slab\nallocator and acquire n-\u003elist_lock that the interrupted context is\nalready holding, corrupting slab state.\n\nWith CONFIG_DEBUG_SPINLOCK on UP, the following BUG is triggered with\nthe slub_kunit test module:\n\n  BUG: spinlock trylock failure on UP on CPU#0, kunit_try_catch/243\n  [...]\n  Call Trace:\n   \u003cNMI\u003e\n   dump_stack_lvl+0x3f/0x60\n   do_raw_spin_trylock+0x41/0x50\n   _raw_spin_trylock+0x24/0x50\n   get_from_partial_node+0x120/0x4d0\n   ___slab_alloc+0x8a/0x4c0\n   kmalloc_nolock_noprof+0x164/0x310\n   [...]\n   \u003c/NMI\u003e\n\nFix this by returning NULL early when invoked from NMI on a UP kernel."
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    "redhat_vex": {
      "aggregate_severity": "None",
      "current_release_date": "2026-06-28T07:40:37+00:00",
      "cve": "CVE-2026-46029",
      "id": "CVE-2026-46029",
      "initial_release_date": "2026-05-27T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: mm/slab: return NULL early from kmalloc_nolock() in NMI on UP",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-46029.json",
      "version": "3"
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      "current_release_date": "2026-08-06T01:18:31Z",
      "cve": "CVE-2026-46029",
      "id": "CVE-2026-46029",
      "initial_release_date": "2026-05-28T03:54:05Z",
      "product_status:known_not_affected": "293",
      "product_status:recommended": "4",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-46029",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-46029.json",
      "version": "7"
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}