CVE-2026-68196 Overview
CVE-2026-68196 is an out-of-bounds read vulnerability in the Linux kernel wilc1000 Wi-Fi driver. The flaw resides in wilc_parse_assoc_resp_info(), which subtracts the size of the fixed association-response header from the received frame length without first validating that the buffer is large enough. A malformed association response shorter than the 6-byte fixed header causes the length calculation to wrap, leading to a large kmemdup() copy past the end of the driver buffer.
Critical Impact
An attacker within Wi-Fi range can send a crafted association response to trigger an out-of-bounds read, potentially leaking kernel memory, crashing the host, or causing a malformed short frame to be treated as a successful association.
Affected Products
- Linux kernel wilc1000 Wi-Fi driver (drivers/net/wireless/microchip/wilc1000)
- Linux distributions shipping the affected wilc1000 driver
- Embedded and IoT platforms using Microchip WILC1000 Wi-Fi modules
Discovery Timeline
- 2026-08-10 - CVE-2026-68196 published to the National Vulnerability Database (NVD)
- 2026-08-13 - Last updated in NVD database
Technical Details for CVE-2026-68196
Vulnerability Analysis
The vulnerability is an out-of-bounds read [CWE-125] in the Linux kernel's wilc1000 wireless driver. The function wilc_parse_assoc_resp_info() calculates the length of the trailing Information Elements (IEs) with the expression ies_len = buffer_len - sizeof(*res);. The value buffer_len originates from host_int_parse_assoc_resp_info(), which forwards hif_drv->assoc_resp and assoc_resp_info_len from a received association-response frame without validation.
When buffer_len is smaller than sizeof(struct wilc_assoc_resp) (6 bytes), the unsigned subtraction wraps. For a 4-byte response, the result is truncated to a u16 value of 65534. The driver then calls kmemdup() to copy 65534 bytes starting at buffer + sizeof(*res), reading far beyond the valid frame data. A response shorter than four bytes additionally triggers an out-of-bounds read of res->status_code at offsets 2 and 3.
A second logic issue compounds the impact. On the short-frame path the parser does not set conn_info->status to a failure code. The caller subsequently checks conn_info->status == WLAN_STATUS_SUCCESS, so a malformed short response can be treated as a successful association.
Root Cause
The root cause is missing input validation on attacker-controlled frame length before pointer arithmetic on a fixed-size header. The driver trusts buffer_len from a received wireless frame and performs an unchecked subtraction, producing a wrapped value used directly as a copy size.
Attack Vector
Exploitation requires adjacent-network access, meaning the attacker must be within radio range of a vulnerable station. An attacker spoofing or acting as an access point can transmit an association response frame shorter than 6 bytes. The vulnerable station parses the frame in kernel context, triggering the out-of-bounds read during kmemdup(). No authentication or user interaction is required. The vulnerability affects confidentiality through kernel memory disclosure and availability through likely kernel oops or panic.
No public proof-of-concept exploit is available in the referenced sources. See the kernel commit fix for the upstream patch adding the length check.
Detection Methods for CVE-2026-68196
Indicators of Compromise
- Kernel oops or panic messages referencing wilc_parse_assoc_resp_info, host_int_parse_assoc_resp_info, or kmemdup in dmesg or system logs.
- Repeated Wi-Fi disconnects or driver resets on hosts using the wilc1000 driver in proximity to unknown or rogue access points.
- KASAN slab-out-of-bounds reports involving the wilc1000 driver on kernels with KASAN enabled.
Detection Strategies
- Monitor kernel ring buffer and journalctl -k output for stack traces originating in drivers/net/wireless/microchip/wilc1000.
- Correlate wireless connection failure events with the presence of nearby unmanaged access points advertising the target SSID.
- Deploy KASAN or KMSAN in test environments to catch triggering of the out-of-bounds read during interoperability testing.
Monitoring Recommendations
- Alert on kernel crashes on IoT and embedded devices running the wilc1000 driver, especially devices deployed in public or shared Wi-Fi environments.
- Track running kernel versions against distribution advisories to identify unpatched hosts.
- Log wireless environment scans to detect rogue APs impersonating enterprise SSIDs targeting affected devices.
How to Mitigate CVE-2026-68196
Immediate Actions Required
- Update the Linux kernel to a version containing the upstream fix referenced in the stable kernel commits listed under External References.
- Inventory all hosts and embedded devices using the Microchip WILC1000 module and prioritize firmware or kernel updates for those exposed to untrusted wireless environments.
- Restrict affected devices to trusted, authenticated wireless networks until patches are deployed.
Patch Information
The fix rejects association-response frames shorter than sizeof(struct wilc_assoc_resp) before computing ies_len or accessing header fields, and sets conn_info->status to a failure value on the short-frame path so the caller does not treat malformed frames as successful associations. Stable kernel patches are available in the following commits: 4c4c97b6, 4d410320, 584c8954, 8ccdf8c8, and e511e93a.
Workarounds
- Unload the wilc1000 module (modprobe -r wilc1000) on systems that do not require it until a patched kernel is installed.
- Disable Wi-Fi on affected embedded devices or move them to wired connectivity where feasible.
- Configure managed access-point profiles with strong authentication (WPA2/WPA3-Enterprise) to reduce exposure to rogue APs sending crafted frames, noting that authentication alone does not prevent all pre-association frame processing.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
