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Fencer Vulns
high 8.1

CVE-2024-44973 json

mm, slub: do not call do_slab_free for kfence object

published 2024-09-04 2 y ago modified 2026-08-05 3 mo ago also EUVD-2024-41175

cvss
8.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 38%
public exploits
0
none known

Summary

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.

Patch / fix

  • Linux Linux 6.10.5, 6.11
  • linux Debian 14, Debian 13 6.10.6-1

debian advisories DEBIAN-CVE-2024-44973

  • linux Ubuntu 24.04 LTS 6.8.0-50.51
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1020.22
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1019.21
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1015.19
  • linux-ibm Ubuntu 24.04 LTS 6.8.0-1017.17
  • linux-azure Ubuntu 24.04 LTS 6.8.0-1020.23
  • linux-gkeop Ubuntu 24.04 LTS 6.8.0-1002.4
  • linux-raspi Ubuntu 24.04 LTS 6.8.0-1016.18

ubuntu advisories UBUNTU-CVE-2024-44973

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

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-2024-44973 updated cvss 5.5

kernel: mm, slub: do not call do_slab_free for kfence object

  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 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
    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

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.44% chance of exploitation in the next 30 days, higher than 38% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
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.