iommufd: IOMMUFD_DESTROY should not increase the refcount

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2023-53795
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2025-12-09 01:16:51 UTC
Updated2026-08-04 10:19:21 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: iommufd: IOMMUFD_DESTROY should not increase the refcount syzkaller found a race where IOMMUFD_DESTROY increments the refcount: obj = iommufd_get_object(ucmd->ictx, cmd->id, IOMMUFD_OBJ_ANY); if (IS_ERR(obj)) return PTR_ERR(obj); iommufd_ref_to_users(obj); /* See iommufd_ref_to_users() */ if (!iommufd_object_destroy_user(ucmd->ictx, obj)) As part of the sequence to join the two existing primitives together. Allowing the refcount the be elevated without holding the destroy_rwsem violates the assumption that all temporary refcount elevations are protected by destroy_rwsem. Racing IOMMUFD_DESTROY with iommufd_object_destroy_user() will cause spurious failures: WARNING: CPU: 0 PID: 3076 at drivers/iommu/iommufd/device.c:477 iommufd_access_destroy+0x18/0x20 drivers/iommu/iommufd/device.c:478 Modules linked in: CPU: 0 PID: 3076 Comm: syz-executor.0 Not tainted 6.3.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/03/2023 RIP: 0010:iommufd_access_destroy+0x18/0x20 drivers/iommu/iommufd/device.c:477 Code: e8 3d 4e 00 00 84 c0 74 01 c3 0f 0b c3 0f 1f 44 00 00 f3 0f 1e fa 48 89 fe 48 8b bf a8 00 00 00 e8 1d 4e 00 00 84 c0 74 01 c3 <0f> 0b c3 0f 1f 44 00 00 41 57 41 56 41 55 4c 8d ae d0 00 00 00 41 RSP: 0018:ffffc90003067e08 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff888109ea0300 RCX: 0000000000000000 RDX: 0000000000000001 RSI: 0000000000000000 RDI: 00000000ffffffff RBP: 0000000000000004 R08: 0000000000000000 R09: ffff88810bbb3500 R10: ffff88810bbb3e48 R11: 0000000000000000 R12: ffffc90003067e88 R13: ffffc90003067ea8 R14: ffff888101249800 R15: 00000000fffffffe FS: 00007ff7254fe6c0(0000) GS:ffff888237c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000555557262da8 CR3: 000000010a6fd000 CR4: 0000000000350ef0 Call Trace: <TASK> iommufd_test_create_access drivers/iommu/iommufd/selftest.c:596 [inline] iommufd_test+0x71c/0xcf0 drivers/iommu/iommufd/selftest.c:813 iommufd_fops_ioctl+0x10f/0x1b0 drivers/iommu/iommufd/main.c:337 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __x64_sys_ioctl+0x84/0xc0 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x38/0x80 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd The solution is to not increment the refcount on the IOMMUFD_DESTROY path at all. Instead use the xa_lock to serialize everything. The refcount check == 1 and xa_erase can be done under a single critical region. This avoids the need for any refcount incrementing. It has the downside that if userspace races destroy with other operations it will get an EBUSY instead of waiting, but this is kind of racing is already dangerous.

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

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

EPSS: 0.001280000 probability, percentile 0.028240000 (date 2026-08-05)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 2ff4bed7fee72ba1abfcff5f11ae8f8e570353f2 495b327435b0298e9b3b434f5834d459a93673ce git Not specified
CNA Linux Linux affected 2ff4bed7fee72ba1abfcff5f11ae8f8e570353f2 99f98a7c0d6985d5507c8130a981972e4b7b3bdc git Not specified
CNA Linux Linux affected 6.2 Not specified
CNA Linux Linux unaffected 6.2 semver Not specified
CNA Linux Linux unaffected 6.4.8 6.4.* semver Not specified
CNA Linux Linux unaffected 6.5 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/99f98a7c0d6985d5507c8130a981972e4b7b3bdc 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/495b327435b0298e9b3b434f5834d459a93673ce 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

© CVE.report 2026

Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties, implied or otherwise, with regard to this information or its use. Any use of this information is at the user's risk. It is the responsibility of user to evaluate the accuracy, completeness or usefulness of any information, opinion, advice or other content. EACH USER WILL BE SOLELY RESPONSIBLE FOR ANY consequences of his or her direct or indirect use of this web site. ALL WARRANTIES OF ANY KIND ARE EXPRESSLY DISCLAIMED. This site will NOT BE LIABLE FOR ANY DIRECT, INDIRECT or any other kind of loss.

CVE, CWE, and OVAL are registred trademarks of The MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. This site includes MITRE data granted under the following license.

Free CVE JSON API cve.report/api

CVE.report and Source URL Uptime Status status.cve.report