CVE-2022-1679 Overview
CVE-2022-1679 is a use-after-free vulnerability [CWE-416] in the Linux kernel's Atheros ath9k_htc wireless adapter driver. The flaw resides in the ath9k_htc_wait_for_target function, which can be forced to fail through specific input messages. When this failure path is triggered, the driver dereferences memory that has already been freed.
A local authenticated user can exploit this condition to crash the system or escalate privileges. The vulnerability affects the Linux kernel, Debian Linux 10, and several NetApp HCI firmware products.
Critical Impact
Local attackers with low privileges can trigger memory corruption in the kernel via the ath9k_htc driver, leading to denial of service or privilege escalation to root.
Affected Products
- Linux Kernel (multiple versions prior to upstream fix)
- Debian Linux 10
- NetApp HCI compute and storage nodes (H300S/H500S/H700S, H300E/H500E/H700E, H410S, H410C firmware)
Discovery Timeline
- 2022-05-16 - CVE-2022-1679 published to NVD
- 2022-06-29 - NetApp publishes security advisory NTAP-20220629-0007
- 2022-10 - Debian LTS issues security announcement for affected packages
- 2024-11-21 - Last updated in NVD database
Technical Details for CVE-2022-1679
Vulnerability Analysis
The Atheros ath9k_htc driver supports USB-attached 802.11n wireless adapters that use Host Target Communication (HTC) firmware. During device initialization, the driver calls ath9k_htc_wait_for_target to synchronize with the target firmware and confirm it is ready to process commands.
When specific malformed or unexpected input messages cause ath9k_htc_wait_for_target to return an error, the cleanup path frees driver resources but leaves dangling pointers reachable from other code paths. Subsequent operations dereference these freed objects, producing classic use-after-free behavior in kernel context.
Because the flaw lives in kernel memory management, successful exploitation grants attackers control over freed slab objects. An attacker who reclaims the freed allocation with controlled data can pivot the dangling pointer into arbitrary write primitives, enabling escalation from an unprivileged local account to root.
Root Cause
The root cause is incorrect error-path handling in the ath9k_htc initialization sequence. Resources released after ath9k_htc_wait_for_target failure are not invalidated in all referencing structures, violating the kernel's object lifetime contract and producing a use-after-free condition tracked under [CWE-416].
Attack Vector
Exploitation requires local access and the ability to interact with the ath9k_htc driver, typically by attaching or simulating an Atheros HTC USB wireless device. The attacker triggers the failure condition in ath9k_htc_wait_for_target by sending crafted input messages, then races to reclaim the freed kernel object before it is reused legitimately. No user interaction beyond the attacker's own actions is required.
A functional exploit has not been publicly released, and the issue is not listed in the CISA Known Exploited Vulnerabilities catalog. Refer to the Kernel Mailing List Discussion for upstream technical analysis.
Detection Methods for CVE-2022-1679
Indicators of Compromise
- Unexpected kernel oops or panic messages referencing ath9k_htc or ath9k_htc_wait_for_target in dmesg or /var/log/kern.log
- KASAN reports flagging use-after-free in ath9k_htc module memory
- Unexplained USB device attach/detach events for Atheros HTC wireless adapters on systems that do not normally use such hardware
Detection Strategies
- Inventory running kernel versions against the fixed versions listed in the Debian LTS Security Announcement and the NetApp Security Advisory
- Monitor for kernel module load events for ath9k_htc on servers where wireless drivers should not be present
- Correlate kernel crashes with subsequent privilege changes, new SUID binaries, or unexpected root-owned processes
Monitoring Recommendations
- Forward kernel ring buffer and audit logs to a centralized SIEM for correlation across hosts
- Alert on USB device insertion events on production servers using udev and auditd rules
- Track package versions for linux-image-* across the fleet and flag any host running an unpatched kernel
How to Mitigate CVE-2022-1679
Immediate Actions Required
- Apply the latest Linux kernel updates from your distribution vendor to patched versions referenced in the upstream fix
- For Debian 10 systems, install the kernel updates from the Debian LTS Security Announcement
- For NetApp HCI nodes, follow remediation guidance in the NetApp Security Advisory
- Reboot affected hosts after kernel installation to activate the patched image
Patch Information
The upstream Linux kernel fix corrects the error-handling path in ath9k_htc_wait_for_target so that freed resources are no longer referenced after failure. Distribution-specific patched packages are available from Debian and NetApp. Discussion of the fix is available on the Linux Kernel Mailing List.
Workarounds
- Blacklist the ath9k_htc kernel module on systems that do not require Atheros USB wireless support
- Restrict physical and logical USB access on multi-user systems to prevent attachment of attacker-controlled wireless devices
- Enforce least-privilege account policies to limit the attack surface available to local users
# Blacklist the vulnerable driver until patching is complete
echo "blacklist ath9k_htc" | sudo tee /etc/modprobe.d/blacklist-ath9k_htc.conf
sudo update-initramfs -u
sudo modprobe -r ath9k_htc 2>/dev/null || true
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
