CVE-2025-21994 json
ksmbd: fix incorrect validation for num_aces field of smb_acl
published 2025-04-02 19 mo ago modified 2026-08-05 3 mo ago also EUVD-2025-9522
- cvss
- 7.6
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 23%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- Linux Linux 5.15.180, 6.1.132, 6.6.85, 6.12.21, 6.13.9, 6.14
- linux Debian 12 6.1.133-1
- linux Debian 14, Debian 13 6.12.21-1
debian advisories DEBIAN-CVE-2025-21994
- linux Ubuntu 22.04 LTS 5.15.0-142.152
- linux Ubuntu 24.04 LTS 6.8.0-84.84
- linux-aws Ubuntu 22.04 LTS 5.15.0-1086.93
- linux-aws Ubuntu 24.04 LTS 6.8.0-1039.41
- linux-gcp Ubuntu 22.04 LTS 5.15.0-1085.94
- linux-gcp Ubuntu 24.04 LTS 6.8.0-1040.42
- linux-gke Ubuntu 22.04 LTS 5.15.0-1083.89
- linux-gke Ubuntu 24.04 LTS 6.8.0-1036.40
ubuntu advisories UBUNTU-CVE-2025-21994
Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0
- git.kernel.org/stable/c/c3a3484d9d31b27a3db0fab91fcf191132d65236 commit
- git.kernel.org/stable/c/9c4e202abff45f8eac17989e549fc7a75095f675 commit
- git.kernel.org/stable/c/d0f87370622a853b57e851f7d5a5452b72300f19 commit
- git.kernel.org/stable/c/a4cb17797a5d241f1e509cb5b46ed95a80c2f5fd commit
- git.kernel.org/stable/c/f6a6721802ac2f12f4c1bbe839a4c229b61866f2 commit
- git.kernel.org/stable/c/1b8b67f3c5e5169535e26efedd3e422172e2db64 commit
Vendor advisories
What the vendors themselves say about their products: affected, fixed or not affected, and what to do.
red hat product security vex CVE-2025-21994 updated cvss 5.5
kernel: ksmbd: fix incorrect validation for num_aces field of smb_acl
-
Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat Enterprise Linux 10 kernelnot affected: vulnerable code not present
Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf
Exploit prediction
0.31% chance of exploitation in the next 30 days, higher than 23% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 7.6 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H |
| NVD | 3.1 | 5.5 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
Affected products
- Linux Linux
Classification
- Technology feeds
References
-
git.kernel.org
/stable/c/c3a3484d9d31b27a3db0fab91fcf191132d65236
patch
-
git.kernel.org
/stable/c/9c4e202abff45f8eac17989e549fc7a75095f675
patch
-
git.kernel.org
/stable/c/d0f87370622a853b57e851f7d5a5452b72300f19
patch
-
git.kernel.org
/stable/c/a4cb17797a5d241f1e509cb5b46ed95a80c2f5fd
patch
-
git.kernel.org
/stable/c/f6a6721802ac2f12f4c1bbe839a4c229b61866f2
patch
-
git.kernel.org
/stable/c/1b8b67f3c5e5169535e26efedd3e422172e2db64
patch
- lists.debian.org /debian-lts-announce/2025/05/msg00045.html
Sources
- CVE List CVE-2025-21994
- NVD CVE-2025-21994
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