CVE-2025-38566: Linux Kernel

High severity, CVSS 7.5. EPSS: 0.6% chance of exploitation in the next 30 days.

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.

Affected products

• Linux Linux Kernel: from 6.4, before 6.6.102 (fixed in 6.6.102); from 6.7, before 6.12.42 (fixed in 6.12.42); from 6.13, before 6.15.10 (fixed in 6.15.10); from 6.16, before 6.16.1 (fixed in 6.16.1); version 6.17 only

Published 2025-08-19. Last modified 2026-07-30.