A NULL pointer dereference was found in the Linux kernel's KVM when dirty ring logging is enabled without an active vCPU context. An unprivileged local attacker on the host may use this flaw to cause a kernel oops condition and thus a denial of service by issuing a KVM_XEN_HVM_SET_ATTR ioctl. This flaw affects Linux kernel versions prior to 5.17-rc1.

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

  - A NULL pointer dereference was found in the Linux kernel's KVM when dirty ring logging is enabled without     an active vCPU context. An unprivileged local attacker on the host may use this flaw to cause a kernel     oops condition and thus a denial of service by issuing a KVM_XEN_HVM_SET_ATTR ioctl. This flaw affects     Linux kernel versions prior to 5.17-rc1. (CVE-2021-4095)

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

The remote Oracle Linux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2022-9534 advisory.

    - KVM: x86/speculation: Disable Fill buffer clear within guests (Pawan Gupta)  [Orabug: 34202258]     {CVE-2022-21123} {CVE-2022-21127} {CVE-2022-21125} {CVE-2022-21166}
    - x86/speculation/mmio: Reuse SRBDS mitigation for SBDS (Pawan Gupta)  [Orabug: 34202258]     {CVE-2022-21123} {CVE-2022-21127} {CVE-2022-21125} {CVE-2022-21166}
    - x86/speculation/srbds: Update SRBDS mitigation selection (Pawan Gupta)  [Orabug: 34202258]     {CVE-2022-21123} {CVE-2022-21127} {CVE-2022-21125} {CVE-2022-21166}
    - x86/speculation/mmio: Add sysfs reporting for Processor MMIO Stale Data (Pawan Gupta)  [Orabug:
    34202258]  {CVE-2022-21123} {CVE-2022-21127} {CVE-2022-21125} {CVE-2022-21166}
    - x86/speculation/mmio: Enable CPU Fill buffer clearing on idle (Pawan Gupta)  [Orabug: 34202258]     {CVE-2022-21123} {CVE-2022-21127} {CVE-2022-21125} {CVE-2022-21166}
    - x86/bugs: Group MDS, TAA & Processor MMIO Stale Data mitigations (Pawan Gupta)  [Orabug: 34202258]     {CVE-2022-21123} {CVE-2022-21127} {CVE-2022-21125} {CVE-2022-21166}
    - x86/speculation/mmio: Add mitigation for Processor MMIO Stale Data (Pawan Gupta)  [Orabug: 34202258]     {CVE-2022-21123} {CVE-2022-21127} {CVE-2022-21125} {CVE-2022-21166}
    - x86/speculation: Add a common function for MD_CLEAR mitigation update (Pawan Gupta)  [Orabug: 34202258]     {CVE-2022-21123} {CVE-2022-21127} {CVE-2022-21125} {CVE-2022-21166}
    - x86/speculation/mmio: Enumerate Processor MMIO Stale Data bug (Pawan Gupta)  [Orabug: 34202258]     {CVE-2022-21123} {CVE-2022-21127} {CVE-2022-21125} {CVE-2022-21166}
    - Documentation: Add documentation for Processor MMIO Stale Data (Pawan Gupta)  [Orabug: 34202258]     {CVE-2022-21123} {CVE-2022-21127} {CVE-2022-21125} {CVE-2022-21166}
    - lockdown: also lock down previous kgdb use (Daniel Thompson)  [Orabug: 34152698]  {CVE-2022-21499}
    - io_uring: fix race between timeout flush and removal (Jens Axboe)  [Orabug: 34115159]  {CVE-2022-29582}
    - KVM: x86: avoid calling x86 emulator without a decoded instruction (Sean Christopherson)  [Orabug:
    34205798]  {CVE-2022-1852} {CVE-2022-1852}
    - perf: Fix sys_perf_event_open() race against self (Peter Zijlstra)  [Orabug: 34172708]  {CVE-2022-1729}
    - af_key: add __GFP_ZERO flag for compose_sadb_supported in function pfkey_register (Haimin Zhang)     [Orabug: 34135342]  {CVE-2022-1353}
    - KVM: avoid NULL pointer dereference in kvm_dirty_ring_push (Paolo Bonzini)  [Orabug: 34048938]     {CVE-2022-1263}
    - can: ems_usb: ems_usb_start_xmit(): fix double dev_kfree_skb() in error path (Hangyu Hua)  [Orabug:
    34048326]  {CVE-2022-28390}
    - can: usb_8dev: usb_8dev_start_xmit(): fix double dev_kfree_skb() in error path (Hangyu Hua)  [Orabug:
    34048287]  {CVE-2022-28388}
    - ALSA: pcm: Fix races among concurrent prealloc proc writes (Takashi Iwai)  [Orabug: 34007904]     {CVE-2022-1048}
    - ALSA: pcm: Fix races among concurrent prepare and hw_params/hw_free calls (Takashi Iwai)  [Orabug:
    34007904]  {CVE-2022-1048}
    - ALSA: pcm: Fix races among concurrent read/write and buffer changes (Takashi Iwai)  [Orabug: 34007904]     {CVE-2022-1048}
    - ALSA: pcm: Fix races among concurrent hw_params and hw_free calls (Takashi Iwai)  [Orabug: 34007904]     {CVE-2022-1048}
    - KVM: x86/mmu: do compare-and-exchange of gPTE via the user address (Paolo Bonzini)  [Orabug: 34034593]     {CVE-2022-1158}
    - netfilter: nf_tables: validate registers coming from userspace. (Pablo Neira Ayuso)  [Orabug: 34012906]     {CVE-2022-1015}
    - netfilter: nf_tables: initialize registers in nft_do_chain() (Pablo Neira Ayuso)  [Orabug: 34012923]     {CVE-2022-1016}

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 Oracle Linux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2022-9533 advisory.

    - KVM: x86/speculation: Disable Fill buffer clear within guests (Pawan Gupta)  [Orabug: 34202258]     {CVE-2022-21123} {CVE-2022-21127} {CVE-2022-21125} {CVE-2022-21166}
    - x86/speculation/mmio: Reuse SRBDS mitigation for SBDS (Pawan Gupta)  [Orabug: 34202258]     {CVE-2022-21123} {CVE-2022-21127} {CVE-2022-21125} {CVE-2022-21166}
    - x86/speculation/srbds: Update SRBDS mitigation selection (Pawan Gupta)  [Orabug: 34202258]     {CVE-2022-21123} {CVE-2022-21127} {CVE-2022-21125} {CVE-2022-21166}
    - x86/speculation/mmio: Add sysfs reporting for Processor MMIO Stale Data (Pawan Gupta)  [Orabug:
    34202258]  {CVE-2022-21123} {CVE-2022-21127} {CVE-2022-21125} {CVE-2022-21166}
    - x86/speculation/mmio: Enable CPU Fill buffer clearing on idle (Pawan Gupta)  [Orabug: 34202258]     {CVE-2022-21123} {CVE-2022-21127} {CVE-2022-21125} {CVE-2022-21166}
    - x86/bugs: Group MDS, TAA & Processor MMIO Stale Data mitigations (Pawan Gupta)  [Orabug: 34202258]     {CVE-2022-21123} {CVE-2022-21127} {CVE-2022-21125} {CVE-2022-21166}
    - x86/speculation/mmio: Add mitigation for Processor MMIO Stale Data (Pawan Gupta)  [Orabug: 34202258]     {CVE-2022-21123} {CVE-2022-21127} {CVE-2022-21125} {CVE-2022-21166}
    - x86/speculation: Add a common function for MD_CLEAR mitigation update (Pawan Gupta)  [Orabug: 34202258]     {CVE-2022-21123} {CVE-2022-21127} {CVE-2022-21125} {CVE-2022-21166}
    - x86/speculation/mmio: Enumerate Processor MMIO Stale Data bug (Pawan Gupta)  [Orabug: 34202258]     {CVE-2022-21123} {CVE-2022-21127} {CVE-2022-21125} {CVE-2022-21166}
    - Documentation: Add documentation for Processor MMIO Stale Data (Pawan Gupta)  [Orabug: 34202258]     {CVE-2022-21123} {CVE-2022-21127} {CVE-2022-21125} {CVE-2022-21166}
    - lockdown: also lock down previous kgdb use (Daniel Thompson)  [Orabug: 34152698]  {CVE-2022-21499}
    - io_uring: fix race between timeout flush and removal (Jens Axboe)  [Orabug: 34115159]  {CVE-2022-29582}
    - KVM: x86: avoid calling x86 emulator without a decoded instruction (Sean Christopherson)  [Orabug:
    34205798]  {CVE-2022-1852} {CVE-2022-1852}
    - perf: Fix sys_perf_event_open() race against self (Peter Zijlstra)  [Orabug: 34172708]  {CVE-2022-1729}
    - af_key: add __GFP_ZERO flag for compose_sadb_supported in function pfkey_register (Haimin Zhang)     [Orabug: 34135342]  {CVE-2022-1353}
    - KVM: avoid NULL pointer dereference in kvm_dirty_ring_push (Paolo Bonzini)  [Orabug: 34048938]     {CVE-2022-1263}
    - can: ems_usb: ems_usb_start_xmit(): fix double dev_kfree_skb() in error path (Hangyu Hua)  [Orabug:
    34048326]  {CVE-2022-28390}
    - can: usb_8dev: usb_8dev_start_xmit(): fix double dev_kfree_skb() in error path (Hangyu Hua)  [Orabug:
    34048287]  {CVE-2022-28388}
    - ALSA: pcm: Fix races among concurrent prealloc proc writes (Takashi Iwai)  [Orabug: 34007904]     {CVE-2022-1048}
    - ALSA: pcm: Fix races among concurrent prepare and hw_params/hw_free calls (Takashi Iwai)  [Orabug:
    34007904]  {CVE-2022-1048}
    - ALSA: pcm: Fix races among concurrent read/write and buffer changes (Takashi Iwai)  [Orabug: 34007904]     {CVE-2022-1048}
    - ALSA: pcm: Fix races among concurrent hw_params and hw_free calls (Takashi Iwai)  [Orabug: 34007904]     {CVE-2022-1048}
    - KVM: x86/mmu: do compare-and-exchange of gPTE via the user address (Paolo Bonzini)  [Orabug: 34034593]     {CVE-2022-1158}
    - netfilter: nf_tables: validate registers coming from userspace. (Pablo Neira Ayuso)  [Orabug: 34012906]     {CVE-2022-1015}
    - netfilter: nf_tables: initialize registers in nft_do_chain() (Pablo Neira Ayuso)  [Orabug: 34012923]     {CVE-2022-1016}

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.

ID	Name	Product	Family	Severity
224289	Linux Distros Unpatched Vulnerability : CVE-2021-4095	Nessus	Misc.	medium
162661	Oracle Linux 8 : Unbreakable Enterprise kernel-container (ELSA-2022-9534)	Nessus	Oracle Linux Local Security Checks	high
162660	Oracle Linux 8 : Unbreakable Enterprise kernel (ELSA-2022-9533)	Nessus	Oracle Linux Local Security Checks	high

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