Libnfs CVE-2026-57918

Client-side memory-safety failure in libnfs (through 6.0.2, fixed by commit f0b109d/935b8db) lets a malicious or compromised NFS server trigger an unsigned integer underflow in the RPC record-marker handling of rpc_read_from_socket(). When a victim application using libnfs connects to a crafted server, the server can supply a record marker whose declared xid/pdu length is smaller than the size libnfs expects to read, wrapping the length value and driving an oversized READ_IOVEC read with corresponding heap memory disclosure or corruption. There is no public exploit identified at time of analysis and it is not in CISA KEV; exploitation requires the victim to initiate a connection to an attacker-controlled NFS endpoint.