CVE-2025-38571: sunrpc: fix client side handling of tls alerts

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-08-19 · updated 2026-10-15

Description

In the Linux kernel, the following vulnerability has been resolved: sunrpc: fix client side handling of tls alerts A security exploit was discovered in NFS over TLS in tls_alert_recv due to its assumption that there is valid data in the msghdr's iterator's kvec. Instead, this patch proposes the 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 control buffer and read in the control message such as a TLS alert. Scott found that a 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 kernel: from 6.5 before 6.6.102; from 6.7 before 6.12.42; from 6.13 before 6.15.10; from 6.16 before 6.16.1 — fixed in 6.12.42, 6.15.10, 6.16.1, 6.6.102

How to fix

Upgrade to a fixed version: Linux kernel 6.12.42, 6.15.10, 6.16.1, 6.6.102. Check the vendor advisory for mitigations.

References

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