In the Linux kernel, the following vulnerability has been resolved: iommufd: Fix race during abort for file descriptors fput() doesn't actually call file_operations release() synchronously, it puts the file on a work queue and it will be released eventually. This is normally fine, except for iommufd the file and the iommufd_object are tied to gether. The file has the object as it's private_data and holds a users refcount, while the object is expected to remain alive as long as the file is. When the allocation of a new object aborts before installing the file it will fput() the file and then go on to immediately kfree() the obj. This causes a UAF once the workqueue completes the fput() and tries to decrement the users refcount. Fix this by putting the core code in charge of the file lifetime, and call __fput_sync() during abort to ensure that release() is called before kfree. __fput_sync() is a bit too tricky to open code in all the object implementations. Instead the objects tell the core code where the file pointer is and the core will take care of the life cycle. If the object is successfully allocated then the file will hold a users refcount and the iommufd_object cannot be destroyed. It is worth noting that close(); ioctl(IOMMU_DESTROY); doesn't have an issue because close() is already using a synchronous version of fput(). The UAF looks like this: BUG: KASAN: slab-use-after-free in iommufd_eventq_fops_release+0x45/0xc0 drivers/iommu/iommufd/eventq.c:376 Write of size 4 at addr ffff888059c97804 by task syz.0.46/6164 CPU: 0 UID: 0 PID: 6164 Comm: syz.0.46 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xcd/0x630 mm/kasan/report.c:482 kasan_report+0xe0/0x110 mm/kasan/report.c:595 check_region_inline mm/kasan/generic.c:183 [inline] kasan_check_range+0x100/0x1b0 mm/kasan/generic.c:189 instrument_atomic_read_write include/linux/instrumented.h:96 [inline] atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:400 [inline] __refcount_dec include/linux/refcount.h:455 [inline] refcount_dec include/linux/refcount.h:476 [inline] iommufd_eventq_fops_release+0x45/0xc0 drivers/iommu/iommufd/eventq.c:376 __fput+0x402/0xb70 fs/file_table.c:468 task_work_run+0x14d/0x240 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop+0xeb/0x110 kernel/entry/common.c:43 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x41c/0x4c0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The remote AlmaLinux 10 host has packages installed that are affected by multiple vulnerabilities as referenced in the ALSA-2026:0453 advisory.

    * kernel: HID: multitouch: fix slab out-of-bounds access in mt_report_fixup() (CVE-2025-39806)
      * kernel: audit: fix out-of-bounds read in audit_compare_dname_path() (CVE-2025-39840)
      * kernel: mm: slub: avoid wake up kswapd in set_track_prepare (CVE-2025-39843)
      * kernel: net: phylink: add lock for serializing concurrent pl->phydev writes with resolver     (CVE-2025-39905)
      * kernel: iommufd: Fix race during abort for file descriptors (CVE-2025-39966)
      * kernel: tls: wait for pending async decryptions if tls_strp_msg_hold fails (CVE-2025-40176)
      * kernel: sctp: avoid NULL dereference when chunk data buffer is missing (CVE-2025-40240)
      * kernel: drm/vmwgfx: Validate command header size against SVGA_CMD_MAX_DATASIZE (CVE-2025-40277)
      * kernel: usb: dwc3: Fix race condition between concurrent dwc3_remove_requests() call paths     (CVE-2025-68287)

Tenable has extracted the preceding description block directly from the AlmaLinux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote RockyLinux 10 host has packages installed that are affected by multiple vulnerabilities as referenced in the RLSA-2026:0453 advisory.

    * kernel: HID: multitouch: fix slab out-of-bounds access in mt_report_fixup() (CVE-2025-39806)

    * kernel: audit: fix out-of-bounds read in audit_compare_dname_path() (CVE-2025-39840)

    * kernel: mm: slub: avoid wake up kswapd in set_track_prepare (CVE-2025-39843)

    * kernel: net: phylink: add lock for serializing concurrent pl->phydev writes with resolver     (CVE-2025-39905)

    * kernel: iommufd: Fix race during abort for file descriptors (CVE-2025-39966)

    * kernel: tls: wait for pending async decryptions if tls_strp_msg_hold fails (CVE-2025-40176)

    * kernel: sctp: avoid NULL dereference when chunk data buffer is missing (CVE-2025-40240)

    * kernel: drm/vmwgfx: Validate command header size against SVGA_CMD_MAX_DATASIZE (CVE-2025-40277)

    * kernel: usb: dwc3: Fix race condition between concurrent dwc3_remove_requests() call paths     (CVE-2025-68287)

Tenable has extracted the preceding description block directly from the RockyLinux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Redhat Enterprise Linux 10 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:0453 advisory.

    The kernel packages contain the Linux kernel, the core of any Linux operating system.

    Security Fix(es):

    * kernel: HID: multitouch: fix slab out-of-bounds access in mt_report_fixup() (CVE-2025-39806)

    * kernel: audit: fix out-of-bounds read in audit_compare_dname_path() (CVE-2025-39840)

    * kernel: mm: slub: avoid wake up kswapd in set_track_prepare (CVE-2025-39843)

    * kernel: net: phylink: add lock for serializing concurrent pl->phydev writes with resolver     (CVE-2025-39905)

    * kernel: iommufd: Fix race during abort for file descriptors (CVE-2025-39966)

    * kernel: tls: wait for pending async decryptions if tls_strp_msg_hold fails (CVE-2025-40176)

    * kernel: sctp: avoid NULL dereference when chunk data buffer is missing (CVE-2025-40240)

    * kernel: drm/vmwgfx: Validate command header size against SVGA_CMD_MAX_DATASIZE (CVE-2025-40277)

    * kernel: usb: dwc3: Fix race condition between concurrent dwc3_remove_requests() call paths     (CVE-2025-68287)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote MiracleLinux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the AXSA:2025-11625:100 advisory.

    * kernel: clone_private_mnt(): make sure that caller has CAP_SYS_ADMIN in the right userns     (CVE-2025-38499)
      * kernel: iommufd: Fix race during abort for file descriptors (CVE-2025-39966)
      * kernel: tls: wait for pending async decryptions if tls_strp_msg_hold fails (CVE-2025-40176)

Tenable has extracted the preceding description block directly from the MiracleLinux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Oracle Linux 10 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2026-0453 advisory.

    - usb: dwc3: Fix race condition between concurrent dwc3_remove_requests() call paths (CKI Backport Bot)     [RHEL-137150] {CVE-2025-68287}
    - drm/vmwgfx: Validate command header size against SVGA_CMD_MAX_DATASIZE (CKI Backport Bot) [RHEL-134431]     {CVE-2025-40277}
    - net: phylink: add lock for serializing concurrent pl->phydev writes with resolver (CKI Backport Bot)     [RHEL-129812] {CVE-2025-39905}
    - sctp: avoid NULL dereference when chunk data buffer is missing (CKI Backport Bot) [RHEL-134010]     {CVE-2025-40240}
    - HID: multitouch: fix slab out-of-bounds access in mt_report_fixup() (CKI Backport Bot) [RHEL-124610]     {CVE-2025-39806}
    - audit: fix out-of-bounds read in audit_compare_dname_path() (Richard Guy Briggs) [RHEL-119185]     {CVE-2025-39840}
    - iommufd: Fix race during abort for file descriptors (Eder Zulian) [RHEL-123789] {CVE-2025-39966}
    - mm: slub: avoid wake up kswapd in set_track_prepare (Audra Mitchell) [RHEL-125522] {CVE-2025-39843}
    - tls: wait for pending async decryptions if tls_strp_msg_hold fails (CKI Backport Bot) [RHEL-128866]     {CVE-2025-40176}

Tenable has extracted the preceding description block directly from the Oracle Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote AlmaLinux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the ALSA-2025:23241 advisory.

    * kernel: clone_private_mnt(): make sure that caller has CAP_SYS_ADMIN in the right userns     (CVE-2025-38499)
      * kernel: iommufd: Fix race during abort for file descriptors (CVE-2025-39966)
      * kernel: tls: wait for pending async decryptions if tls_strp_msg_hold fails (CVE-2025-40176)

Tenable has extracted the preceding description block directly from the AlmaLinux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote RockyLinux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RLSA-2025:23241 advisory.

    * kernel: clone_private_mnt(): make sure that caller has CAP_SYS_ADMIN in the right userns     (CVE-2025-38499)

    * kernel: iommufd: Fix race during abort for file descriptors (CVE-2025-39966)

    * kernel: tls: wait for pending async decryptions if tls_strp_msg_hold fails (CVE-2025-40176)

Tenable has extracted the preceding description block directly from the RockyLinux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Oracle Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2025-23241 advisory.

    - CVE-2025-38499 kernel: clone_private_mnt(): make sure that caller has CAP_SYS_ADMIN in the right userns     (Abhi Das) [RHEL-129261] {CVE-2025-38499}
    - tls: wait for pending async decryptions if tls_strp_msg_hold fails (CKI Backport Bot) [RHEL-128860]     {CVE-2025-40176}

Tenable has extracted the preceding description block directly from the Oracle Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Redhat Enterprise Linux 10 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2025:23250 advisory.

    The kernel packages contain the Linux kernel, the core of any Linux operating system.

    Security Fix(es):

    * kernel: clone_private_mnt(): make sure that caller has CAP_SYS_ADMIN in the right userns     (CVE-2025-38499)

    * kernel: iommufd: Fix race during abort for file descriptors (CVE-2025-39966)

    * kernel: net: tun: Update napi->skb after XDP process (CVE-2025-39984)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Redhat Enterprise Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2025:23241 advisory.

    The kernel packages contain the Linux kernel, the core of any Linux operating system.

    Security Fix(es):

    * kernel: clone_private_mnt(): make sure that caller has CAP_SYS_ADMIN in the right userns     (CVE-2025-38499)

    * kernel: iommufd: Fix race during abort for file descriptors (CVE-2025-39966)

    * kernel: tls: wait for pending async decryptions if tls_strp_msg_hold fails (CVE-2025-40176)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Redhat Enterprise Linux 9 host has packages installed that are affected by a vulnerability as referenced in the RHSA-2025:22802 advisory.

    The kernel packages contain the Linux kernel, the core of any Linux operating system.

    Security Fix(es):

    * kernel: iommufd: Fix race during abort for file descriptors (CVE-2025-39966)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - iommufd: Fix race during abort for file descriptors fput() doesn't actually call file_operations release()     synchronously, it puts the file on a work queue and it will be released eventually. This is normally fine,     except for iommufd the file and the iommufd_object are tied to gether. The file has the object as it's     private_data and holds a users refcount, while the object is expected to remain alive as long as the file     is. When the allocation of a new object aborts before installing the file it will fput() the file and then     go on to immediately kfree() the obj. This causes a UAF once the workqueue completes the fput() and tries     to decrement the users refcount. Fix this by putting the core code in charge of the file lifetime, and     call __fput_sync() during abort to ensure that release() is called before kfree. __fput_sync() is a bit     too tricky to open code in all the object implementations. Instead the objects tell the core code where     the file pointer is and the core will take care of the life cycle. If the object is successfully allocated     then the file will hold a users refcount and the iommufd_object cannot be destroyed. It is worth noting     that close(); ioctl(IOMMU_DESTROY); doesn't have an issue because close() is already using a synchronous     version of fput(). The UAF looks like this: BUG: KASAN: slab-use-after-free in     iommufd_eventq_fops_release+0x45/0xc0 drivers/iommu/iommufd/eventq.c:376 Write of size 4 at addr     ffff888059c97804 by task syz.0.46/6164 CPU: 0 UID: 0 PID: 6164 Comm: syz.0.46 Not tainted syzkaller #0     PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025     Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0     lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xcd/0x630     mm/kasan/report.c:482 kasan_report+0xe0/0x110 mm/kasan/report.c:595 check_region_inline     mm/kasan/generic.c:183 [inline] kasan_check_range+0x100/0x1b0 mm/kasan/generic.c:189     instrument_atomic_read_write include/linux/instrumented.h:96 [inline] atomic_fetch_sub_release     include/linux/atomic/atomic-instrumented.h:400 [inline] __refcount_dec include/linux/refcount.h:455     [inline] refcount_dec include/linux/refcount.h:476 [inline] iommufd_eventq_fops_release+0x45/0xc0     drivers/iommu/iommufd/eventq.c:376 __fput+0x402/0xb70 fs/file_table.c:468 task_work_run+0x14d/0x240     kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]     exit_to_user_mode_loop+0xeb/0x110 kernel/entry/common.c:43 exit_to_user_mode_prepare include/linux/irq-     entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]     syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x41c/0x4c0     arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f (CVE-2025-39966)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Severity
291602	AlmaLinux 10 : kernel (ALSA-2026:0453)	Nessus	Alma Linux Local Security Checks	high
291297	RockyLinux 10 : kernel (RLSA-2026:0453)	Nessus	Rocky Linux Local Security Checks	high
283499	RHEL 10 : kernel (RHSA-2026:0453)	Nessus	Red Hat Local Security Checks	high
283169	MiracleLinux 9 : kernel-5.14.0-611.16.1.el9_7 (AXSA:2025-11625:100)	Nessus	Miracle Linux Local Security Checks	medium
282630	Oracle Linux 10 : kernel (ELSA-2026-0453)	Nessus	Oracle Linux Local Security Checks	high
282336	AlmaLinux 9 : kernel (ALSA-2025:23241)	Nessus	Alma Linux Local Security Checks	medium
279628	RockyLinux 9 : kernel (RLSA-2025:23241)	Nessus	Rocky Linux Local Security Checks	high
279383	Oracle Linux 9 : kernel (ELSA-2025-23241)	Nessus	Oracle Linux Local Security Checks	medium
278989	RHEL 10 : kernel (RHSA-2025:23250)	Nessus	Red Hat Local Security Checks	high
278951	RHEL 9 : kernel (RHSA-2025:23241)	Nessus	Red Hat Local Security Checks	high
277858	RHEL 9 : kernel (RHSA-2025:22802)	Nessus	Red Hat Local Security Checks	high
271558	Linux Distros Unpatched Vulnerability : CVE-2025-39966	Nessus	Misc.	medium

Detections

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CVE-2025-39966

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