CVE-2024-49938 is a vulnerability identified in the Linux kernel specifically affecting the ath9k_htc wireless driver, which handles certain Atheros USB Wi-Fi chipsets. The issue arises from improper handling of socket buffer (skb) length resetting before USB Request Block (URB) resubmissions. The vulnerable code uses skb_trim() to reset the skb length, but skb_trim() performs a sanity check on the existing skb length, which can be uninitialized in some error paths, potentially leading to undefined behavior or memory corruption. The fix involves replacing skb_trim() with __skb_set_length(skb, 0), which directly sets the skb length to zero without relying on the sanity check, and also removes redundant calls to skb_reset_tail_pointer() since __skb_set_length() already performs this action. The vulnerability was reported by Syzbot, an automated kernel fuzzer, and affects the ath9k_hif_usb_reg_in_cb() and ath9k_hif_usb_rx_cb() functions. Although no known exploits are currently reported in the wild, the flaw could theoretically be triggered by crafted USB traffic to vulnerable devices, potentially leading to kernel memory corruption or denial of service. The affected Linux kernel versions are identified by specific commit hashes, indicating the issue is present in recent kernel versions prior to the patch. This vulnerability is technical and low-level, involving kernel memory management in wireless USB drivers, and requires local or USB-level interaction to exploit.

For European organizations, this vulnerability poses a risk primarily to systems running Linux kernels with the vulnerable ath9k_htc driver enabled and using affected Atheros USB Wi-Fi chipsets. Potential impacts include system instability, kernel crashes (denial of service), or in worst cases, privilege escalation or arbitrary code execution if memory corruption is exploited. This could disrupt critical network connectivity in environments relying on these Wi-Fi devices, affecting operational continuity. Given the ubiquity of Linux in enterprise servers, embedded systems, and IoT devices, organizations with wireless infrastructure or endpoint devices using these drivers could face increased risk. The impact is heightened in sectors with stringent availability requirements such as telecommunications, manufacturing, and critical infrastructure. However, exploitation requires USB-level access or local interaction, limiting remote attack vectors. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially from targeted attackers or insiders.

European organizations should promptly apply Linux kernel updates that include the patch replacing skb_trim() with __skb_set_length() in the ath9k_htc driver. System administrators should verify kernel versions and update to the latest stable releases from trusted sources. For devices where kernel updates are delayed or unavailable, consider disabling or unloading the ath9k_htc module if feasible, or restricting USB device access to trusted peripherals only. Implement USB device control policies to prevent unauthorized USB devices from connecting to critical systems. Conduct thorough inventory and auditing of wireless hardware to identify affected devices. Employ kernel hardening techniques such as kernel address space layout randomization (KASLR) and memory protection features to reduce exploitation likelihood. Monitor system logs for unusual kernel errors or crashes related to USB wireless drivers. Finally, maintain robust endpoint security and network segmentation to limit the impact of potential compromises.