Highly exploitable, CVE-2021-47441 poses a critical security risk that could lead to severe breaches.
Status: Awaiting Analysis
Last updated: 🕡 21 Nov 2024, 06:36 UTC
Originally published on: 🕖 22 May 2024, 07:15 UTC
Time between publication and last update: 182 days
CVSS Release: version 3
134c704f-9b21-4f2e-91b3-4a467353bcc0
Secondary
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H
CVE-2021-47441: In the Linux kernel, the following vulnerability has been resolved: mlxsw: thermal: Fix out-of-bounds memory accesses Currently, mlxsw allows cooling states to be set above the maximum cooling state supported by the driver: # cat /sys/class/thermal/thermal_zone2/cdev0/type mlxsw_fan # cat /sys/class/thermal/thermal_zone2/cdev0/max_state 10 # echo 18 > /sys/class/thermal/thermal_zone2/cdev0/cur_state # echo $? 0 This results in out-of-bounds memory accesses when thermal state transition statistics are enabled (CONFIG_THERMAL_STATISTICS=y), as the transition table is accessed with a too large index (state) [1]. According to the thermal maintainer, it is the responsibility of the driver to reject such operations [2]. Therefore, return an error when the state to be set exceeds the maximum cooling state supported by the driver. To avoid dead code, as suggested by the thermal maintainer [3], partially revert commit a421ce088ac8 ("mlxsw: core: Extend cooling device with cooling levels") that tried to interpret these invalid cooling states (above the maximum) in a special way. The cooling levels array is not removed in order to prevent the fans going below 20% PWM, which would cause them to get stuck at 0% PWM. [1] BUG: KASAN: slab-out-of-bounds in thermal_cooling_device_stats_update+0x271/0x290 Read of size 4 at addr ffff8881052f7bf8 by task kworker/0:0/5 CPU: 0 PID: 5 Comm: kworker/0:0 Not tainted 5.15.0-rc3-custom-45935-gce1adf704b14 #122 Hardware name: Mellanox Technologies Ltd. "MSN2410-CB2FO"/"SA000874", BIOS 4.6.5 03/08/2016 Workqueue: events_freezable_power_ thermal_zone_device_check Call Trace: dump_stack_lvl+0x8b/0xb3 print_address_description.constprop.0+0x1f/0x140 kasan_report.cold+0x7f/0x11b thermal_cooling_device_stats_update+0x271/0x290 __thermal_cdev_update+0x15e/0x4e0 thermal_cdev_update+0x9f/0xe0 step_wise_throttle+0x770/0xee0 thermal_zone_device_update+0x3f6/0xdf0 process_one_work+0xa42/0x1770 worker_thread+0x62f/0x13e0 kthread+0x3ee/0x4e0 ret_from_fork+0x1f/0x30 Allocated by task 1: kasan_save_stack+0x1b/0x40 __kasan_kmalloc+0x7c/0x90 thermal_cooling_device_setup_sysfs+0x153/0x2c0 __thermal_cooling_device_register.part.0+0x25b/0x9c0 thermal_cooling_device_register+0xb3/0x100 mlxsw_thermal_init+0x5c5/0x7e0 __mlxsw_core_bus_device_register+0xcb3/0x19c0 mlxsw_core_bus_device_register+0x56/0xb0 mlxsw_pci_probe+0x54f/0x710 local_pci_probe+0xc6/0x170 pci_device_probe+0x2b2/0x4d0 really_probe+0x293/0xd10 __driver_probe_device+0x2af/0x440 driver_probe_device+0x51/0x1e0 __driver_attach+0x21b/0x530 bus_for_each_dev+0x14c/0x1d0 bus_add_driver+0x3ac/0x650 driver_register+0x241/0x3d0 mlxsw_sp_module_init+0xa2/0x174 do_one_initcall+0xee/0x5f0 kernel_init_freeable+0x45a/0x4de kernel_init+0x1f/0x210 ret_from_fork+0x1f/0x30 The buggy address belongs to the object at ffff8881052f7800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 1016 bytes inside of 1024-byte region [ffff8881052f7800, ffff8881052f7c00) The buggy address belongs to the page: page:0000000052355272 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1052f0 head:0000000052355272 order:3 compound_mapcount:0 compound_pincount:0 flags: 0x200000000010200(slab|head|node=0|zone=2) raw: 0200000000010200 ffffea0005034800 0000000300000003 ffff888100041dc0 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881052f7a80: 00 00 00 00 00 00 04 fc fc fc fc fc fc fc fc fc ffff8881052f7b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8881052f7b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff8881052f7c00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8881052f7c80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [2] https://lore.kernel.org/linux-pm/9aca37cb-1629-5c67- ---truncated---
The exploitability of CVE-2021-47441 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).
CVE-2021-47441 presents an accessible attack vector with minimal effort required. Restricting access controls and implementing security updates are critical to reducing exploitation risks.
A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.
Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.
Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.
Above is the CVSS Sub-score Breakdown for CVE-2021-47441, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.
Below is the Impact Analysis for CVE-2021-47441, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.
The EPSS score estimates the probability that this vulnerability will be exploited in the near future.
EPSS Score: 0.045% (probability of exploit)
EPSS Percentile: 18.35%
(lower percentile = lower relative risk)
This vulnerability is less risky than approximately 81.65% of others.
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