CVE-2024-44973

mm, slub: do not call do_slab_free for kfence object

Published Sep 4, 2024 CVSS 3.1 · 8.1 High EPSS < 1% KEV · Not listed
Description
In the Linux kernel, the following vulnerability has been resolved:

mm, slub: do not call do_slab_free for kfence object

In 782f8906f805 the freeing of kfence objects was moved from deep
inside do_slab_free to the wrapper functions outside. This is a nice
change, but unfortunately it missed one spot in __kmem_cache_free_bulk.

This results in a crash like this:

BUG skbuff_head_cache (Tainted: G S B E ): Padding overwritten. 0xffff88907fea0f00-0xffff88907fea0fff @offset=3840

slab_err (mm/slub.c:1129)
free_to_partial_list (mm/slub.c:? mm/slub.c:4036)
slab_pad_check (mm/slub.c:864 mm/slub.c:1290)
check_slab (mm/slub.c:?)
free_to_partial_list (mm/slub.c:3171 mm/slub.c:4036)
kmem_cache_alloc_bulk (mm/slub.c:? mm/slub.c:4495 mm/slub.c:4586 mm/slub.c:4635)
napi_build_skb (net/core/skbuff.c:348 net/core/skbuff.c:527 net/core/skbuff.c:549)

All the other callers to do_slab_free appear to be ok.

Add a kfence_free check in __kmem_cache_free_bulk to avoid the crash.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Ubuntu USN Ubuntu USN USN-7154-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7155-1 Linux kernel (NVIDIA) vulnerabilities
Ubuntu USN Ubuntu USN USN-7156-1 Linux kernel (GKE) vulnerabilities
Ubuntu USN Ubuntu USN USN-7154-2 Linux kernel (HWE) vulnerabilities
Ubuntu USN Ubuntu USN USN-7196-1 Linux kernel (Azure) vulnerabilities
History
Type Values Removed Values Added
Metrics cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'}

Type Values Removed Values Added
Weaknesses CWE-20
Type Values Removed Values Added
First Time appeared Linux
Linux linux Kernel
Weaknesses NVD-CWE-noinfo
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.11:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.11:rc2:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: mm, slub: do not call do_slab_free for kfence object In 782f8906f805 the freeing of kfence objects was moved from deep inside do_slab_free to the wrapper functions outside. This is a nice change, but unfortunately it missed one spot in __kmem_cache_free_bulk. This results in a crash like this: BUG skbuff_head_cache (Tainted: G S B E ): Padding overwritten. 0xffff88907fea0f00-0xffff88907fea0fff @offset=3840 slab_err (mm/slub.c:1129) free_to_partial_list (mm/slub.c:? mm/slub.c:4036) slab_pad_check (mm/slub.c:864 mm/slub.c:1290) check_slab (mm/slub.c:?) free_to_partial_list (mm/slub.c:3171 mm/slub.c:4036) kmem_cache_alloc_bulk (mm/slub.c:? mm/slub.c:4495 mm/slub.c:4586 mm/slub.c:4635) napi_build_skb (net/core/skbuff.c:348 net/core/skbuff.c:527 net/core/skbuff.c:549) All the other callers to do_slab_free appear to be ok. Add a kfence_free check in __kmem_cache_free_bulk to avoid the crash.
Title mm, slub: do not call do_slab_free for kfence object
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Aug 5, 2026, 11:37 AM
Reserved
Aug 21, 2024, 5:34 AM
Status
Modified
Published
Sep 4, 2024, 7:15 PM
Modified
Aug 4, 2026, 11:20 AM
Severity
Moderate
Public date
Sep 4, 2024, 12:00 AM