CVE-2022-50345: 
Linux Kernel vulnerability analysis and mitigation

CVE-2022-50345 is a vulnerability in the Linux kernel's Network File System daemon (NFSD) component, specifically affecting NFSv3 READ operations. The vulnerability was disclosed and published on September 16, 2025, with the last modification date being September 17, 2025. The issue affects various Linux distributions including Ubuntu and Red Hat Enterprise Linux systems (NVD CVE).

The vulnerability stems from how NFSD handles buffer management. Since before the git era, NFSD has combined RPC receive and send buffers into a single array of pages to conserve memory. When an RPC Call is received, svcprocess() updates svcrqst::rqres to describe the available portion of rqpages for constructing the Reply. This mechanism causes the send buffer (rq_res) to shrink when the received RPC record containing the RPC Call is large. On TCP connections, a client can exploit this by sending a correctly-formed RPC Call header within an excessively large RPC record, preventing the construction of the full maximum payload size (Ubuntu Security).

The vulnerability affects the Linux kernel's NFS server functionality, particularly impacting systems running NFSv3 services. When exploited, it can lead to buffer overflow conditions in the NFSD service, potentially affecting the availability and reliability of NFS services (NVD CVE).

Multiple Linux distributions have released patches to address this vulnerability. Ubuntu has fixed the issue in version 5.15.0-56.62 for Ubuntu 22.04 LTS, version 5.15.0-56.62~20.04.1 for Ubuntu 20.04 LTS with HWE, and various other kernel variants. Similar fixes have been implemented for different kernel versions across multiple Ubuntu releases (Ubuntu Security).