cbcvebase.
CVE-2024-56617
published 2024-12-27

CVE-2024-56617: In the Linux kernel, the following vulnerability has been resolved: cacheinfo: Allocate memory during CPU hotplug if not done from the primary CPU Commit…

PriorityP421medium5.5CVSS 3.1
AVLACLPRLUINSUCNINAH
EPSS
0.20%
10.6th percentile
In the Linux kernel, the following vulnerability has been resolved: cacheinfo: Allocate memory during CPU hotplug if not done from the primary CPU Commit 5944ce092b97 ("arch_topology: Build cacheinfo from primary CPU") adds functionality that architectures can use to optionally allocate and build cacheinfo early during boot. Commit 6539cffa9495 ("cacheinfo: Add arch specific early level initializer") lets secondary CPUs correct (and reallocate memory) cacheinfo data if needed. If the early build functionality is not used and cacheinfo does not need correction, memory for cacheinfo is never allocated. x86 does not use the early build functionality. Consequently, during the cacheinfo CPU hotplug callback, last_level_cache_is_valid() attempts to dereference a NULL pointer: BUG: kernel NULL pointer dereference, address: 0000000000000100 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not present page PGD 0 P4D 0 Oops: 0000 [#1] PREEPMT SMP NOPTI CPU: 0 PID 19 Comm: cpuhp/0 Not tainted 6.4.0-rc2 #1 RIP: 0010: last_level_cache_is_valid+0x95/0xe0a Allocate memory for cacheinfo during the cacheinfo CPU hotplug callback if not done earlier. Moreover, before determining the validity of the last-level cache info, ensure that it has been allocated. Simply checking for non-zero cache_leaves() is not sufficient, as some architectures (e.g., Intel processors) have non-zero cache_leaves() before allocation. Dereferencing NULL cacheinfo can occur in update_per_cpu_data_slice_size(). This function iterates over all online CPUs. However, a CPU may have come online recently, but its cacheinfo may not have been allocated yet. While here, remove an unnecessary indentation in allocate_cache_info(). [ bp: Massage. ]

Affected

12 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 6.12.5-1 (forky)linux 6.12.5-1 (forky)
linuxlinux
linuxlinux>= 6539cffa94957241c096099a57d05fa4d8c7db8a < 23b5908b11b77ff8d7b8f7b8f11cbab2e1f4bfc223b5908b11b77ff8d7b8f7b8f11cbab2e1f4bfc2
linuxlinux>= 6539cffa94957241c096099a57d05fa4d8c7db8a < 95e197354e0de07e9a20819bdae6562e4dda0f2095e197354e0de07e9a20819bdae6562e4dda0f20
linuxlinux>= 6539cffa94957241c096099a57d05fa4d8c7db8a < b3fce429a1e030b50c1c91351d69b8667eef627bb3fce429a1e030b50c1c91351d69b8667eef627b
linuxlinux_kernel
linuxlinux_kernel>= 0 < 6.12.5-16.12.5-1
linuxlinux_kernel>= 0 < 6.12.5-16.12.5-1
linuxlinux_kernel>= 6.4 < 6.6.666.6.66
linuxlinux_kernel>= 6.7 < 6.12.56.12.5
msrcazl3_kernel_6.6.64.2-9_on_azure_linux_3.0
msrcazl3_kernel_6.6.76.1-1_on_azure_linux_3.0

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
osv5.5MEDIUM
vendor_debian5.5LOW
vendor_msrc5.5MEDIUM
vendor_redhat5.5MEDIUM
Stop checking back — get the weekly exploitation signal.

Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.