CVE-2021-47168

A vulnerability was found in the NFS implementation in Linux Kernel causing memory corruption due to an incorrect size limit in filelayout_decode_layout(). Using "sizeof(struct nfs_fh)" instead of NFS_MAXFHSIZE led to buffer overflow by two bytes leads to potential memory corruption.

Red Hat has evaluated this vulnerability as having a Moderate severity because exploitation requires connecting to a malicious or compromised NFSv4.1 server that delivers a crafted pNFS layout structure. In typical Red Hat Enterprise Linux environments, storage shares are mounted exclusively from trusted internal servers, limiting exposure to unauthenticated remote attackers. Furthermore, while the improper size validation produces a small out-of-bounds memory write during layout decoding, the practical impact is constrained to a kernel crash and denial of service rather than arbitrary code execution.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update the affected package as soon as possible.