CVE-2022-48828
CriticalCVSS 9.1Exploitation Probability (EPSS)
Low risk47th percentile - higher than 47% of all known CVEs
Summary
In the Linux kernel, in NFSD, an underflow issue with ia_size was fixed. Since ia_size is a signed loff_t and NFS file size is unsigned, large values could cause underflow. A check was added in nfsd_setattr().
Risk Assessment
The underflow could lead to incorrect behavior of the NFS server, potentially allowing an attacker to cause unexpected behavior.
Recommendation
Apply the Linux kernel update containing the fix for NFSD.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: NFSD: Fix ia_size underflow iattr::ia_size is a loff_t, which is a signed 64-bit type. NFSv3 and NFSv4 both define file size as an unsigned 64-bit type. Thus there is a range of valid file size values an NFS client can send that is already larger than Linux can handle. Currently decode_fattr4() dumps a full u64 value into ia_size. If that value happens to be larger than S64_MAX, then ia_size underflows. I'm about to fix up the NFSv3 behavior as well, so let's catch the underflow in the common code path: nfsd_setattr().