CVE-2025-38566: linux kernel — Fix

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 iterator before calling into the tls_alert_recv.

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CVSS v3.1 Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-754 CWE-754

Affected Products

Vendor	Product	Versions
linux	linux_kernel	6.4 — 6.6.102
linux	linux_kernel	6.7 — 6.12.42
linux	linux_kernel	6.13 — 6.15.10
linux	linux_kernel	6.16 — 6.16.1
linux	linux_kernel	All

References

Advisories & Patches

https://git.kernel.org/stable/c/25bb3647d30a20486b5fe7cff2b0e503c16c9692 https://git.kernel.org/stable/c/3b549da875414989f480b66835d514be80a0bd9c https://git.kernel.org/stable/c/6b33c31cc788073bfbed9297e1f4486ed73d87da https://git.kernel.org/stable/c/b1df394621710b312f0393e3f240fdac0764f968 https://git.kernel.org/stable/c/bee47cb026e762841f3faece47b51f985e215edb

Frequently Asked Questions

What is CVE-2025-38566? +

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. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2025-38566? +

CVE-2025-38566 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2025-38566? +

CVE-2025-38566 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-38566? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2025-38566