CVE-2021-47633 ath5k: fix OOB in ath5k_eeprom_read_pcal_info_5111
An out-of-bounds write in the ath5k wireless driver allows attackers to cause memory corruption, potentially leading to code execution or system crashes.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2021-47633?
CVE-2021-47633 is a high-severity memory corruption vulnerability in Linux kernel, published on 26 Feb 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
ath5k: fix OOB in ath5k_eeprom_read_pcal_info_5111
The bug was found during fuzzing. Stacktrace locates it in ath5k_eeprom_convert_pcal_info_5111. When none of the curve is selected in the loop, idx can go up to AR5K_EEPROM_N_PD_CURVES. The line makes pd out of bound. pd = &chinfo[pier].pd_curves[idx];
There are many OOB writes using pd later in the code. So I added a sanity check for idx. Checks for other loops involving AR5K_EEPROM_N_PD_CURVES are not needed as the loop index is not used outside the loops.
The patch is NOT tested with real device.
The following is the fuzzing report
BUG: KASAN: slab-out-of-bounds in ath5k_eeprom_read_pcal_info_5111+0x126a/0x1390 [ath5k] Write of size 1 at addr ffff8880174a4d60 by task modprobe/214
CPU: 0 PID: 214 Comm: modprobe Not tainted 5.6.0 #1 Call Trace: dump_stack+0x76/0xa0 print_address_description.constprop.0+0x16/0x200 ? ath5k_eeprom_read_pcal_info_5111+0x126a/0x1390 [ath5k] ? ath5k_eeprom_read_pcal_info_5111+0x126a/0x1390 [ath5k] __kasan_report.cold+0x37/0x7c ? ath5k_eeprom_read_pcal_info_5111+0x126a/0x1390 [ath5k] kasan_report+0xe/0x20 ath5k_eeprom_read_pcal_info_5111+0x126a/0x1390 [ath5k] ? apic_timer_interrupt+0xa/0x20 ? ath5k_eeprom_init_11a_pcal_freq+0xbc0/0xbc0 [ath5k] ? ath5k_pci_eeprom_read+0x228/0x3c0 [ath5k] ath5k_eeprom_init+0x2513/0x6290 [ath5k] ? ath5k_eeprom_init_11a_pcal_freq+0xbc0/0xbc0 [ath5k] ? usleep_range+0xb8/0x100 ? apic_timer_interrupt+0xa/0x20 ? ath5k_eeprom_read_pcal_info_2413+0x2f20/0x2f20 [ath5k] ath5k_hw_init+0xb60/0x1970 [ath5k] ath5k_init_ah+0x6fe/0x2530 [ath5k] ? kasprintf+0xa6/0xe0 ? ath5k_stop+0x140/0x140 [ath5k] ? _dev_notice+0xf6/0xf6 ? apic_timer_interrupt+0xa/0x20 ath5k_pci_probe.cold+0x29a/0x3d6 [ath5k] ? ath5k_pci_eeprom_read+0x3c0/0x3c0 [ath5k] ? mutex_lock+0x89/0xd0 ? ath5k_pci_eeprom_read+0x3c0/0x3c0 [ath5k] local_pci_probe+0xd3/0x160 pci_device_probe+0x23f/0x3e0 ? pci_device_remove+0x280/0x280 ? pci_device_remove+0x280/0x280 really_probe+0x209/0x5d0
Weakness: CWE-125
Which versions are affected by CVE-2021-47633?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2021-47633?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2021-47633 being exploited?
There is no known exploitation of CVE-2021-47633 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2021-47633, GHSA-hh39-hp2x-qgp5, UBUNTU-CVE-2021-47633.