CVE-2025-38434 Affecting linux-virt-doc package, versions <6.12.37-r0


Severity

Recommended
0.0
medium
0
10

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Threat Intelligence

EPSS
0.02% (5th percentile)

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  • Snyk IDSNYK-MINIMOSLATEST-LINUXVIRTDOC-14082617
  • published21 Nov 2025
  • disclosed25 Jul 2025

Introduced: 25 Jul 2025

CVE-2025-38434  (opens in a new tab)

How to fix?

Upgrade Minimos:latest linux-virt-doc to version 6.12.37-r0 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream linux-virt-doc package and not the linux-virt-doc package as distributed by Minimos. See How to fix? for Minimos:latest relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

Revert "riscv: Define TASK_SIZE_MAX for __access_ok()"

This reverts commit ad5643cf2f69 ("riscv: Define TASK_SIZE_MAX for __access_ok()").

This commit changes TASK_SIZE_MAX to be LONG_MAX to optimize access_ok(), because the previous TASK_SIZE_MAX (default to TASK_SIZE) requires some computation.

The reasoning was that all user addresses are less than LONG_MAX, and all kernel addresses are greater than LONG_MAX. Therefore access_ok() can filter kernel addresses.

Addresses between TASK_SIZE and LONG_MAX are not valid user addresses, but access_ok() let them pass. That was thought to be okay, because they are not valid addresses at hardware level.

Unfortunately, one case is missed: get_user_pages_fast() happily accepts addresses between TASK_SIZE and LONG_MAX. futex(), for instance, uses get_user_pages_fast(). This causes the problem reported by Robert [1].

Therefore, revert this commit. TASK_SIZE_MAX is changed to the default: TASK_SIZE.

This unfortunately reduces performance, because TASK_SIZE is more expensive to compute compared to LONG_MAX. But correctness first, we can think about optimization later, if required.

CVSS Base Scores

version 3.1