CVE-2022-50080: 
Linux Kernel vulnerability analysis and mitigation

CVE-2022-50080 is a vulnerability discovered in the Linux kernel's tee subsystem, specifically in the registershmhelper() function. The vulnerability was disclosed on June 18, 2025, affecting the Linux kernel's memory management functionality. The issue occurs when special lengths are supplied by user space, causing an integer overflow when calculating the number of pages covered by a supplied user space memory region (NVD).

The vulnerability manifests in the registershmhelper() function where an integer overflow occurs during page number calculations. This leads to internalgetuserpagesfast(), a helper function of pinuserpagesfast(), performing a NULL pointer dereference at virtual address 0x10. The issue can be traced through a call sequence involving internalgetuserpagesfast, pinuserpagesfast, registershmhelper, teeshmregisteruserbuf, teeioctl, and invokesyscall functions (NVD, Wiz).

When exploited, this vulnerability can cause a kernel crash through NULL pointer dereference, potentially leading to a denial of service condition on affected systems (Wiz).

The vulnerability has been fixed by adding an explicit call to accessok() in teeshmregisteruser_buf() to catch invalid user space addresses early in the process. This preventive check helps identify and handle invalid user space addresses before they can cause the NULL pointer dereference (NVD, Wiz).