CVE-2025-38257: debian linux — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: s390/pkey: Prevent overflow in size calculation for memdup_user() Number of apqn target list entries contained in 'nr_apqns' variable is determined by userspace via an ioctl call so the result of the product in calculation of size passed to memdup_user() may overflow. In this case the actual size of the allocated area and the value describing it won't be in sync leading to various types of unpredictable behaviour later. Use a proper memdup_array_user() helper which returns an error if an overflow is detected. Note that it is different from when nr_apqns is initially zero - that case is considered valid and should be handled in subsequent pkey_handler implementations. Found by Linux Verification Center (linuxtesting.org).

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CVSS v3.1 Score

7.8

HIGH

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

Affected Products

Vendor	Product	Versions
linux	linux_kernel	5.4 — 5.15.187
linux	linux_kernel	5.16 — 6.1.143
linux	linux_kernel	6.2 — 6.6.96
linux	linux_kernel	6.7 — 6.12.36
linux	linux_kernel	6.13 — 6.15.5
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
debian	debian_linux	All

References

Advisories & Patches

https://git.kernel.org/stable/c/73483ca7e07a5e39bdf612eec9d3d293e8bef649 https://git.kernel.org/stable/c/7360ee47599af91a1d5f4e74d635d9408a54e489 https://git.kernel.org/stable/c/88f3869649edbc4a13f6c2877091f81cd5a50f05 https://git.kernel.org/stable/c/ad1bdd24a02d5a8d119af8e4cd50933780a6d29f https://git.kernel.org/stable/c/f855b119e62b004a5044ed565f2a2b368c4d3f16 https://git.kernel.org/stable/c/faa1ab4a23c42e34dc000ef4977b751d94d5148c

Other References

https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html

Frequently Asked Questions

What is CVE-2025-38257? +

In the Linux kernel, the following vulnerability has been resolved: s390/pkey: Prevent overflow in size calculation for memdup_user() Number of apqn target list entries contained in 'nr_apqns' variable is determined by userspace via an ioctl call so the result of the product in calculation of size passed to memdup_user() may overflow. In this case the actual size of the allocated area and the value describing it won't be in sync leading to various types of unpredictable behaviour later. Use a proper memdup_array_user() helper which returns an error if an overflow is detected. Note that it is different from when nr_apqns is initially zero - that case is considered valid and should be handled in subsequent pkey_handler implementations. Found by Linux Verification Center (linuxtesting.org). It has a CVSS v3.1 base score of 7.8 (HIGH).

How severe is CVE-2025-38257? +

CVE-2025-38257 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2025-38257? +

CVE-2025-38257 affects products from debian, linux, specifically: debian_linux, linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-38257? +

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-2025-38257