CVE-2026-22978 in Linux
Summary
by MITRE • 01/23/2026
In the Linux kernel, the following vulnerability has been resolved:
wifi: avoid kernel-infoleak from struct iw_point
struct iw_point has a 32bit hole on 64bit arches.
struct iw_point {
void __user *pointer; /* Pointer to the data (in user space) */ __u16 length; /* number of fields or size in bytes */ __u16 flags; /* Optional params */ };
Make sure to zero the structure to avoid disclosing 32bits of kernel data to user space.
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Analysis
by VulDB Data Team • 05/17/2026
The vulnerability CVE-2026-22978 represents a kernel information leak in the Linux wireless subsystem that arises from improper memory initialization within the struct iw_point data structure. This issue specifically affects 64-bit architectures where the structure contains a 32-bit padding hole between its pointer and length fields, creating a potential information disclosure channel. The wireless subsystem utilizes this structure to handle ioctl operations for wireless configuration parameters, making it a critical component in the kernel's network security posture. The vulnerability stems from the fact that when kernel code initializes this structure, it fails to properly zero out all fields, leaving residual kernel memory contents accessible to user-space applications through the wireless ioctl interface.
The technical flaw manifests in the memory layout of struct iw_point where the 64-bit pointer field is immediately followed by a 16-bit length field and another 16-bit flags field, creating a 32-bit gap in memory alignment on 64-bit systems. When the kernel processes wireless ioctl commands and populates this structure, the uninitialized padding bytes retain whatever data was previously stored in that memory location. This memory garbage can contain sensitive kernel information such as stack contents, kernel addresses, or other internal data structures that should remain confidential. The vulnerability is particularly dangerous because it allows unprivileged user-space processes to potentially extract kernel memory contents through carefully crafted wireless ioctl operations that return the struct iw_point to user space.
The operational impact of this information leak extends beyond simple data disclosure, as it can significantly weaken the security of the entire system by providing attackers with kernel memory layout information that could be leveraged in more sophisticated attacks. According to CWE-200, this vulnerability falls under "Information Exposure" and represents a classic case of uninitialized memory disclosure that can aid in bypassing security mechanisms like kernel address space layout randomization. The vulnerability affects any system running the Linux kernel with wireless capabilities, particularly those using wireless drivers that implement the wireless extensions interface. Attackers could potentially use this information to perform kernel exploitation techniques, including address leak attacks, or to gain insights into kernel memory structures that could aid in crafting more effective exploits against other vulnerabilities.
Mitigation strategies for CVE-2026-22978 focus on ensuring proper initialization of the struct iw_point structure before it is returned to user space. The recommended approach involves explicitly zeroing the entire structure using functions like memset before populating its fields, which prevents any residual kernel data from being exposed to user-space applications. This solution aligns with the principle of least privilege and secure coding practices outlined in various security frameworks, including those referenced by the ATT&CK framework under techniques related to information gathering and privilege escalation. System administrators should ensure their kernels are updated with the patched version that implements proper zero-initialization of the structure, while developers should review similar patterns in other kernel data structures to prevent analogous issues. The fix typically involves adding a single memset call before the structure is populated, making it a straightforward and low-risk mitigation that addresses the root cause without introducing performance penalties or breaking existing functionality.