CVE-2026-22978: 
Linux Kernel vulnerability analysis and mitigation

CVE-2026-22978 is a kernel information disclosure vulnerability in the Linux kernel's wireless interface handling, specifically caused by an uninitialized 32-bit padding hole in struct iw_point on 64-bit architectures. The structure — used in wireless ioctl operations — was not zeroed before being copied to user space, allowing a local low-privileged user to read 32 bits of uninitialized kernel memory. It was published on January 23, 2026, and affects Linux kernel versions from 2.6.27 through multiple stable branches up to 6.19-rc4. It carries a CVSS v3.1 base score of 3.3 (Low) (Red Hat CVE, Feedly).

The root cause is an uninitialized memory disclosure (related to CWE-200: Exposure of Sensitive Information) arising from a 32-bit alignment hole in struct iw_point on 64-bit systems. The structure contains a void __user *pointer (8 bytes on 64-bit), followed by two __u16 fields (length and flags), leaving a 4-byte implicit padding gap that the compiler inserts for alignment but does not zero. When the kernel copies this structure to user space during wireless ioctl handling without first zeroing it, the padding bytes may contain stale kernel stack or heap data. Exploitation requires local access with low privileges and no user interaction — an attacker simply invokes the relevant wireless ioctl and reads the returned structure to extract the leaked bytes (Feedly, Red Hat CVE).

The vulnerability has a confidentiality-only impact: a local attacker with low privileges can read 32 bits of uninitialized kernel memory per exploitation attempt. There is no integrity or availability impact. While the direct data exposure is limited, the leaked kernel memory could aid an attacker in bypassing kernel address space layout randomization (KASLR) or other security mechanisms as part of a broader privilege escalation chain (Feedly).

Patches have been applied across multiple Linux kernel stable branches. Administrators should upgrade to the following fixed versions based on their current branch: 5.10.248 or later (5.10.x), 5.15.198 or later (5.15.x), 6.1.161 or later (6.1.x), 6.6.121 or later (6.6.x), 6.12.66 or later (6.12.x), or 6.18.6 or later (6.18.x). Microsoft has also released a patch for its CBL-Mariner kernel (cbl2_kernel_5.15.186.1-1 and later). As a compensating control while patches are being deployed, restricting local user access on multi-user 64-bit Linux systems reduces exposure. Patch commits are available in the Linux kernel stable trees (Feedly, Red Hat Bugzilla, Microsoft MSRC).

Red Hat tracked the issue via Bugzilla (BZ#2432383) and published a CVE advisory. Microsoft acknowledged the vulnerability in its Security Response Center and released a patch for the CBL-Mariner kernel. The Yocto Project security mailing list also discussed the issue in the context of embedded Linux distributions. Coverage has been largely routine, with no notable researcher commentary or significant community debate given the low severity rating (Red Hat CVE, Microsoft MSRC).