CVE-2025-38566

/// Technical description

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 iterat

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References