CVE-2025-21994

ksmbd: fix incorrect validation for num_aces field of smb_acl

7.6 HighFix available

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.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: Low
User interaction: None

What an attacker can affect

Confidentiality: Low
Integrity: Low
Availability: High

Exploit likelihood

0.31%Up 0.3 points since Apr 3, 2025

What each source reports

CVE List Score used 7.6

ksmbd: fix incorrect validation for num_aces field of smb_acl

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.

Record: CVE-2025-21994
CVSS 3.1: 7.6 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H
Updated: 2026-11-02

EUVDEUVD-2025-9522 7.6

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.

Record: EUVD-2025-9522
CVSS 3.1: 7.6 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H
Updated: 2026-11-02

GitHub AdvisoriesGHSA-pcv3-r2v8-4964 5.5

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix incorrect...

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.

Record: GHSA-pcv3-r2v8-4964
CVSS 3.1: 5.5 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

NVD 7.6

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.

Record: CVE-2025-21994
CVSS 3.1: 7.6 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H
CVSS 3.1: 5.5 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSVBELL-CVE-2025-21994 5.5

Record: BELL-CVE-2025-21994
CVSS 3.1: 5.5 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSV 7.6

ksmbd: fix incorrect validation for num_aces field of smb_acl

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.

Record: CVE-2025-21994
CVSS 3.1: 7.6 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H
Updated: 2026-11-02

Show 38 moreShow less

OSVDEBIAN-CVE-2025-21994 5.5

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.

Record: DEBIAN-CVE-2025-21994
CVSS 3.1: 5.5 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSVOESA-2025-1446 7.8

kernel security update

The Linux Kernel, the operating system core itself.

Security Fix(es):

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

ntb_hw_switchtec: Fix shift-out-of-bounds in switchtec_ntb_mw_set_trans

There is a kernel API ntb_mw_clear_trans() would pass 0 to both addr and size. This would make xlate_pos negative.

[ 23.734156] switchtec switchtec0: MW 0: part 0 addr 0x0000000000000000 size 0x0000000000000000 [ 23.734158] ================================================================================ [ 23.734172] UBSAN: shift-out-of-bounds in drivers/ntb/hw/mscc/ntb_hw_switchtec.c:293:7 [ 23.734418] shift exponent -1 is negative

Ensuring xlate_pos is a positive or zero before BIT.(CVE-2023-53034)

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

drm/msm/gem: prevent integer overflow in msm_ioctl_gem_submit()

The "submit->cmd[i].size" and "submit->cmd[i].offset" variables are u32 values that come from the user via the submit_lookup_cmds() function. This addition could lead to an integer wrapping bug so use size_add() to prevent that.

Patchwork: https://patchwork.freedesktop.org/patch/624696/(CVE-2024-52559)

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

fs/ntfs3: Mark inode as bad as soon as error detected in mi_enum_attr()

Extended the mi_enum_attr() function interface with an additional parameter, struct ntfs_inode *ni, to allow marking the inode as bad as soon as an error is detected.(CVE-2024-52560)

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

crypto: qat/qat_4xxx - fix off by one in uof_get_name()

The fw_objs[] array has "num_objs" elements so the > needs to be >= to prevent an out of bounds read.(CVE-2024-53162)

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

smb: client: fix use-after-free of signing key

Customers have reported use-after-free in @ses->auth_key.response with SMB2.1 + sign mounts which occurs due to following race:

task A task B cifs_mount() dfs_mount_share() get_session() cifs_mount_get_session() cifs_send_recv() cifs_get_smb_ses() compound_send_recv() cifs_setup_session() smb2_setup_request() kfree_sensitive() smb2_calc_signature() crypto_shash_setkey() UAF

Fix this by ensuring that we have a valid @ses->auth_key.response by checking whether @ses->ses_status is SES_GOOD or SES_EXITING with @ses->ses_lock held. After commit 24a9799aa8ef ("smb: client: fix UAF in smb2_reconnect_server()"), we made sure to call ->logoff() only when @ses was known to be good (e.g. valid ->auth_key.response), so it's safe to access signing key when @ses->ses_status == SES_EXITING.(CVE-2024-53179)

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

scsi: ufs: bsg: Set bsg_queue to NULL after removal

Currently, this does not cause any issues, but I believe it is necessary to set bsg_queue to NULL after removing it to prevent potential use-after-free (UAF) access.(CVE-2024-54458)

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

KVM: x86: Play nice with protected guests in complete_hypercall_exit()

Use is_64_bit_hypercall() instead of is_64_bit_mode() to detect a 64-bit hypercall when completing said hypercall. For guests with protected state, e.g. SEV-ES and SEV-SNP, KVM must assume the hypercall was made in 64-bit mode as the vCPU state needed to detect 64-bit mode is unavailable.

Hacking the sev_smoke_test selftest to generate a KVM_HC_MAP_GPA_RANGE hypercall via VMGEXIT trips the WARN:

------------[ cut here ]------------ WARNING: CPU: 273 PID: 326626 at arch/x86/kvm/x86.h:180 complete_hypercall_exit+0x44/0xe0 [kvm] Modules linked in: kvm_amd kvm ... [last unloaded: kvm] CPU: 273 UID: 0 PID: 326626 Comm: sev_smoke_test Not tainted 6.12.0-smp--392e932fa0f3-feat…

Record: OESA-2025-1446
CVSS 3.1: 7.8 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Updated: 2026-11-02

OSVOESA-2025-1450 7.8

kernel security update

The Linux Kernel, the operating system core itself.

Security Fix(es):

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

ntb_hw_switchtec: Fix shift-out-of-bounds in switchtec_ntb_mw_set_trans

There is a kernel API ntb_mw_clear_trans() would pass 0 to both addr and size. This would make xlate_pos negative.

Ensuring xlate_pos is a positive or zero before BIT.(CVE-2023-53034)

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

f2fs: fix to shrink read extent node in batches

We use rwlock to protect core structure data of extent tree during its shrink, however, if there is a huge number of extent nodes in extent tree, during shrink of extent tree, it may hold rwlock for a very long time, which may trigger kernel hang issue.

This patch fixes to shrink read extent node in batches, so that, critical region of the rwlock can be shrunk to avoid its extreme long time hold.(CVE-2024-41935)

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

vrf: revert "vrf: Remove unnecessary RCU-bh critical section"

This reverts commit 504fc6f4f7f681d2a03aa5f68aad549d90eab853.

dev_queue_xmit_nit is expected to be called with BH disabled. __dev_queue_xmit has the following:

    /* Disable soft irqs for various locks below. Also
     * stops preemption for RCU.
     */
    rcu_read_lock_bh();

VRF must follow this invariant. The referenced commit removed this protection. Which triggered a lockdep warning:

================================
WARNING: inconsistent lock state
6.11.0 #1 Tainted: G        W
--------------------------------
inconsistent {IN-SOFTIRQ-W} -&gt; {SOFTIRQ-ON-W} usage.
btserver/134819 [HC0[0]:SC0[0]:HE1:SE1] takes:
ffff8882da30c118 (rlock-AF_PACKET){+.?.}-{2:2}, at: tpacket_rcv+0x863/0x3b30
{IN-SOFTIRQ-W} state was registered at:
  lock_acquire+0x19a/0x4f0
  _raw_spin_lock+0x27/0x40
  packet_rcv+0xa33/0x1320
  __netif_receive_skb_core.constprop.0+0xcb0/0x3a90
  __netif_receive_skb_list_core+0x2c9/0x890
  netif_receive_skb_list_internal+0x610/0xcc0
      [...]

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(rlock-AF_PACKET);
  &lt;Interrupt&gt;
    lock(rlock-AF_PACKET);

 *** DEADLOCK ***

Call Trace:
 &lt;TASK&gt;
 dump_stack_lvl+0x73/0xa0
 mark_lock+0x102e/0x16b0
 __lock_acquire+0x9ae/0x6170
 lock_acquire+0x19a/0x4f0
 _raw_spin_lock+0x27/0x40
 tpacket_rcv+0x863/0x3b30
 dev_queue_xmit_nit+0x709/0xa40
 vrf_finish_direct+0x26e/0x340 [vrf]
 vrf_l3_out+0x5f4/0xe80 [vrf]
 __ip_local_out+0x51e/0x7a0
      [...](CVE-2024-49980)

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

drm/msm/gem: prevent integer overflow in msm_ioctl_gem_submit()

Patchwork: https://patchwork.freedesktop.org/patch/624696/(CVE-2024-52559)

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

fs/ntfs3: Mark inode as bad as soon as error detected in mi_enum_attr()

Extended the mi_enum_attr() function interface with an additional parameter, struct ntfs_inode *ni, to allow marking the inode as bad as soon as an error is detected.(CVE-2024-52560)

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

crypto: qat/qat_4xxx - fix off by one in uof_get_name()

The fw_objs[] array has "num_objs" elements so the > needs to be >= to…

Record: OESA-2025-1450
CVSS 3.1: 7.8 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Updated: 2026-11-02

OSVROOT-OS-UBUNTU-2404-CVE-2025-21994 5.5

CVE-2025-21994 in linux - Patched by Root

Root has patched CVE-2025-21994 in the linux package for Root:Ubuntu:24.04. Multiple fixed versions available.

Record: ROOT-OS-UBUNTU-2404-CVE-2025-21994
CVSS 3.1: 5.5 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-06

OSVUBUNTU-CVE-2025-21994 7.1

Record: UBUNTU-CVE-2025-21994
CVSS 4.0: 7.1 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N
CVSS 3.1: 5.5 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CVSS 3.1: 7.6 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H
Updated: 2026-11-11

OSVMGASA-2025-0142 No score

Updated kernel, kmod-virtualbox & kmod-xtables-addons packages fix security vulnerabilities

Upstream kernel version 6.6.87 fixes bugs and vulnerabilities. The kmod-virtualbox and kmod-xtables-addons packages have been updated to work with this new kernel. For information about the vulnerabilities see the links.

Record: MGASA-2025-0142
Updated: 2026-11-02

OSVMGASA-2025-0146 No score

Updated kernel-linus packages fix security vulnerabilities

Vanilla upstream kernel version 6.6.88 fixes bugs and vulnerabilities. For information about the vulnerabilities see the links.

Record: MGASA-2025-0146
Updated: 2026-11-02

OSVUSN-7591-1 No score

linux, linux-gcp, linux-gke, linux-gkeop, linux-ibm, linux-kvm, linux-lowlatency, linux-nvidia, linux-nvidia-tegra, linux-nvidia-tegra-igx, linux-oracle vulnerabilities

Michael Randrianantenaina discovered that the Bluetooth driver in the Linux Kernel contained an improper access control vulnerability. A nearby attacker could use this to connect a rougue device and possibly execute arbitrary code. (CVE-2024-8805)

It was discovered that the CIFS network file system implementation in the Linux kernel did not properly verify the target namespace when handling upcalls. An attacker could use this to expose sensitive information. (CVE-2025-2312)