CVE-2025-21994: linux kernel — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix incorrect validation for num_aces field of smb_acl parse_dcal() validate num_aces to allocate posix_ace_state_array. if (num_aces > ULONG_MAX / sizeof(struct smb_ace *)) It is an incorrect validation that we can create an array of size ULONG_MAX. smb_acl has ->size field to calculate actual number of aces in request buffer size. Use this to check invalid num_aces.

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CVSS v3.1 Score

5.5

MEDIUM

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

Affected Products

Vendor	Product	Versions
linux	linux_kernel	5.15 — 5.15.180
linux	linux_kernel	5.16 — 6.1.132
linux	linux_kernel	6.2 — 6.6.85
linux	linux_kernel	6.7 — 6.12.21
linux	linux_kernel	6.13 — 6.13.9
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All

References

Advisories & Patches

https://git.kernel.org/stable/c/1b8b67f3c5e5169535e26efedd3e422172e2db64 https://git.kernel.org/stable/c/9c4e202abff45f8eac17989e549fc7a75095f675 https://git.kernel.org/stable/c/a4cb17797a5d241f1e509cb5b46ed95a80c2f5fd https://git.kernel.org/stable/c/c3a3484d9d31b27a3db0fab91fcf191132d65236 https://git.kernel.org/stable/c/d0f87370622a853b57e851f7d5a5452b72300f19 https://git.kernel.org/stable/c/f6a6721802ac2f12f4c1bbe839a4c229b61866f2

Other References

https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html

Frequently Asked Questions

What is CVE-2025-21994? +

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix incorrect validation for num_aces field of smb_acl parse_dcal() validate num_aces to allocate posix_ace_state_array. if (num_aces > ULONG_MAX / sizeof(struct smb_ace *)) It is an incorrect validation that we can create an array of size ULONG_MAX. smb_acl has ->size field to calculate actual number of aces in request buffer size. Use this to check invalid num_aces. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2025-21994? +

CVE-2025-21994 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-21994? +

CVE-2025-21994 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-2025-21994? +

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-2025-21994