How severe is CVE-2021-47441?

CVE-2021-47441 has a CVSS 3.x base score of 7.3, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity low, and availability high.

Is CVE-2021-47441 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (14th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-47441?

CVE-2021-47441 primarily affects Linux Linux Kernel. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-47441?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2021-47441 have an EU (EUVD) identifier?

Yes. CVE-2021-47441 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-34446.

When was CVE-2021-47441 published?

CVE-2021-47441 was published on 2024-05-22 and last updated on 2026-06-17.

CVE-2021-47441

CVE-2021-47441 is a high-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 7.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-787.

Key facts

Severity: High (CVSS 3.x base score 7.3)
EPSS exploit prediction: 0% (14th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2021-34446
Weakness: CWE-787
Affected product: Linux Linux Kernel
Published: 2024-05-22
Last modified: 2026-06-17

Description

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---

Frequently asked questions

What is 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---
How severe is CVE-2021-47441?: CVE-2021-47441 has a CVSS 3.x base score of 7.3, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity low, and availability high.
Is CVE-2021-47441 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (14th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-47441?: CVE-2021-47441 primarily affects Linux Linux Kernel. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-47441?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2021-47441 have an EU (EUVD) identifier?: Yes. CVE-2021-47441 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-34446.
When was CVE-2021-47441 published?: CVE-2021-47441 was published on 2024-05-22 and last updated on 2026-06-17.

References

Affected products (6)

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc5:*:*:*:*:*:*

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