CVE-2022-50709 wifi: ath9k: avoid uninit memory read in ath9k_htc_rx_msg()
A local attacker with physical access or USB privileges can trigger an uninitialized memory read in the ath9k WiFi driver, potentially leaking kernel memory contents.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2022-50709?
CVE-2022-50709 is a vulnerability in Linux, published on 24 Dec 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:
wifi: ath9k: avoid uninit memory read in ath9k_htc_rx_msg()
syzbot is reporting uninit value at ath9k_htc_rx_msg() [1], for ioctl(USB_RAW_IOCTL_EP_WRITE) can call ath9k_hif_usb_rx_stream() with pkt_len = 0 but ath9k_hif_usb_rx_stream() uses __dev_alloc_skb(pkt_len + 32, GFP_ATOMIC) based on an assumption that pkt_len is valid. As a result, ath9k_hif_usb_rx_stream() allocates skb with uninitialized memory and ath9k_htc_rx_msg() is reading from uninitialized memory.
Since bytes accessed by ath9k_htc_rx_msg() is not known until ath9k_htc_rx_msg() is called, it would be difficult to check minimal valid pkt_len at "if (pkt_len > 2 * MAX_RX_BUF_SIZE) {" line in ath9k_hif_usb_rx_stream().
We have two choices. One is to workaround by adding __GFP_ZERO so that ath9k_htc_rx_msg() sees 0 if pkt_len is invalid. The other is to let ath9k_htc_rx_msg() validate pkt_len before accessing. This patch chose the latter.
Note that I'm not sure threshold condition is correct, for I can't find details on possible packet length used by this protocol.
Which versions are affected by CVE-2022-50709?
How do I fix CVE-2022-50709?
Apply the vendor's patch.
Is CVE-2022-50709 being exploited?
There is no known exploitation of CVE-2022-50709 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2022-50709, GHSA-cpm8-mrmc-3w57, UBUNTU-CVE-2022-50709.