CVE-2025-38566
CriticalCVSS 9.8Exploitation Probability (EPSS)
Low risk45th percentile - higher than 45% of all known CVEs
Summary
In the Linux kernel's sunrpc module, a vulnerability was found in server-side TLS alert handling. The tls_alert_recv() function incorrectly assumes it can read data from the msg iterator, causing issues with TLS control message processing.
Risk Assessment
The organization is exposed to potential attacks on NFS over TLS, which could lead to data leaks or communication integrity breaches.
Recommendation
Update the Linux kernel to a version containing the fix that reworks how control messages are set up in sock_recvmsg().
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: sunrpc: fix handling of server side tls alerts Scott Mayhew discovered a security exploit in NFS over TLS in tls_alert_recv() due to its assumption it can read data from the msg iterator's kvec.. kTLS implementation splits TLS non-data record payload between the control message buffer (which includes the type such as TLS aler or TLS cipher change) and the rest of the payload (say TLS alert's level/description) which goes into the msg payload buffer. This patch proposes to rework how control messages are setup and used by sock_recvmsg(). If no control message structure is setup, kTLS layer will read and process TLS data record types. As soon as it encounters a TLS control message, it would return an error. At that point, NFS can setup a kvec backed msg buffer and read in the control message such as a TLS alert. Msg iterator can advance the kvec pointer as a part of the copy process thus we need to revert the iterator before calling into the tls_alert_recv.