An issue was discovered in fs/io_uring.c in the Linux kernel through 5.11.8. It allows attackers to cause a denial of service (deadlock) because exit may be waiting to park a SQPOLL thread, but concurrently that SQPOLL thread is waiting for a signal to start, aka CID-3ebba796fa25.

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

  - An issue was discovered in fs/io_uring.c in the Linux kernel through 5.11.8. It allows attackers to cause     a denial of service (deadlock) because exit may be waiting to park a SQPOLL thread, but concurrently that     SQPOLL thread is waiting for a signal to start, aka CID-3ebba796fa25. (CVE-2021-28951)

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

An update of the linux package has been released.

The version of kernel installed on the remote host is prior to 5.10.29-27.126. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2KERNEL-5.10-2024-058 advisory.

    2024-06-06: CVE-2021-28951 was added to this advisory.

    An issue was discovered in fs/io_uring.c in the Linux kernel through 5.11.8. It allows attackers to cause     a denial of service (deadlock) because exit may be waiting to park a SQPOLL thread, but concurrently that     SQPOLL thread is waiting for a signal to start, aka CID-3ebba796fa25. (CVE-2021-28951)

    A remote denial of service vulnerability was found in the Linux kernel's TIPC kernel module. The while     loop in tipc_link_xmit() hits an unknown state while attempting to parse SKBs, which are not in the queue.
    Sending two small UDP packets to a system with a UDP bearer results in the CPU utilization for the system     to instantly spike to 100%, causing a denial of service condition. (CVE-2023-1390)

Tenable has extracted the preceding description block directly from the tested product 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 version of kernel installed on the remote host is prior to 5.15.43-20.103. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2KERNEL-5.15-2023-023 advisory.

    2024-03-13: CVE-2022-48619 was added to this advisory.

    2023-10-12: CVE-2021-3923 was added to this advisory.

    2023-08-31: CVE-2023-4459 was added to this advisory.

    2023-08-31: CVE-2023-1637 was added to this advisory.

    2023-08-31: CVE-2023-4387 was added to this advisory.

    An issue was discovered in fs/io_uring.c in the Linux kernel through 5.11.8. It allows attackers to cause     a denial of service (deadlock) because exit may be waiting to park a SQPOLL thread, but concurrently that     SQPOLL thread is waiting for a signal to start, aka CID-3ebba796fa25. (CVE-2021-28951)

    A flaw was found in the Linux kernel's implementation of RDMA over infiniband. An attacker with a     privileged local account can leak kernel stack information when issuing commands to the     /dev/infiniband/rdma_cm device node. While this access is unlikely to leak sensitive user information, it     can be further used to defeat existing kernel protection mechanisms. (CVE-2021-3923)

    A flaw was found in unrestricted eBPF usage by the BPF_BTF_LOAD, leading to a possible out-of-bounds     memory write in the Linux kernel's BPF subsystem due to the way a user loads BTF. This flaw allows a local     user to crash or escalate their privileges on the system. (CVE-2022-0500)

    A flaw was found in the Linux kernel in linux/net/netfilter/nf_tables_api.c of the netfilter subsystem.
    This flaw allows a local user to cause an out-of-bounds write issue. (CVE-2022-1015)

    A flaw was found in the Linux kernel in net/netfilter/nf_tables_core.c:nft_do_chain, which can cause a     use-after-free. This issue needs to handle return with proper preconditions, as it can lead to a kernel     information leak problem caused by a local, unprivileged attacker. (CVE-2022-1016)

    When the KVM updates the guest's page table entry, it will first use get_user_pages_fast() to pin the     page, and when it fails (e.g. the vma->flags has VM_IO or VM_PFNMAP), it will get corresponding VMA where     the page lies in through find_vma_intersection(), calculate the physical address, and map the page to the     kernel virtual address through memremap(), and finally, write the update.The problem is that when we get     the vma through find_vma_intersection(), only VM_PFNMAP is checked, not both VM_IO and VM_PFNMAP. In the     reproducer below, after the KVM_SET_USER_MEMORY_REGION is completed, we replace the guest's memory mapping     with the kernel-user shared region of io_uring and then perform the KVM_TRANSLATE operation, which finally     triggers the page table entry update. Now, memremap() will return page_offset_base (direct mapping of all     physical memory) + vaddr (the linear address of KVM_TRANSLATE) + vm_pgoff (the offset when io_uring     performs mmap(2)), and use the return value as the base address for CMPXCHG (write 0x21 in this case).
    Since both vaddr and vm_pgoff are controllable by the user-mode process, writing may exceed the previously     mapped guest memory space and trigger exceptions such as UAF. The vulnerability shares similarities with     CVE-2021-22543. (CVE-2022-1158)

    A NULL pointer dereference issue was found in KVM when releasing a vCPU with dirty ring support enabled.
    This flaw allows an unprivileged local attacker on the host to issue specific ioctl calls, causing a     kernel oops condition that results in a denial of service. (CVE-2022-1263)

    A vulnerability was found in the pfkey_register function in net/key/af_key.c in the Linux kernel. This     flaw allows a local, unprivileged user to gain access to kernel memory, leading to a system crash or a     leak of internal kernel information. (CVE-2022-1353)

    perf: Fix sys_perf_event_open() race against self (CVE-2022-1729)

    A flaw was found in the Linux kernel's adjust_ptr_min_max_vals in the kernel/bpf/verifier.c function. In     this flaw, a missing sanity check for *_OR_NULL pointer types that perform pointer arithmetic may cause a     kernel information leak issue. (CVE-2022-23222)

    An integer coercion error was found in the openvswitch kernel module. Given a sufficiently large number of     actions, while copying and reserving memory for a new action of a new flow, the reserve_sfa_size()     function does not return -EMSGSIZE as expected, potentially leading to an out-of-bounds write access. This     flaw allows a local user to crash or potentially escalate their privileges on the system. (CVE-2022-2639)

    The SUNRPC subsystem in the Linux kernel through 5.17.2 can call xs_xprt_free before ensuring that sockets     are in the intended state. (CVE-2022-28893)

    Improper Update of Reference Count vulnerability in net/sched of Linux Kernel allows local attacker to     cause privilege escalation to root. This issue affects: Linux Kernel versions prior to 5.18; version 4.14     and later versions. (CVE-2022-29581)

    A use-after-free flaw was found in the Linux kernel's io_uring interface subsystem in the way a user     triggers a race condition between timeout flush and removal. This flaw allows a local user to crash or     escalate their privileges on the system. (CVE-2022-29582)

    The Linux kernel before 5.17.2 mishandles seccomp permissions. The PTRACE_SEIZE code path allows attackers     to bypass intended restrictions on setting the PT_SUSPEND_SECCOMP flag. (CVE-2022-30594)

    An issue was discovered in drivers/input/input.c in the Linux kernel before 5.17.10. An attacker can cause     a denial of service (panic) because input_set_capability mishandles the situation in which an event code     falls outside of a bitmap. (CVE-2022-48619)

    A flaw that boot CPU could be vulnerable for the speculative execution behavior kind of attacks in the     Linux kernel X86 CPU Power management options functionality was found in the way user resuming CPU from     suspend-to-RAM. A local user could use this flaw to potentially get unauthorized access to some memory of     the CPU similar to the speculative execution behavior kind of attacks. (CVE-2023-1637)

    A use-after-free flaw was found in vhost_net_set_backend in drivers/vhost/net.c in virtio network     subcomponent in the Linux kernel due to a double fget. This flaw could allow a local attacker to crash the     system, and could even lead to a kernel information leak problem. (CVE-2023-1838)

    Improper restriction of operations within the bounds of a memory buffer in some Intel(R) i915 Graphics     drivers for linux before kernel version 6.2.10 may allow an authenticated user to potentially enable     escalation of privilege via local access. (CVE-2023-28410)

    A use-after-free flaw was found in vmxnet3_rq_alloc_rx_buf in drivers/net/vmxnet3/vmxnet3_drv.c in     VMware's vmxnet3 ethernet NIC driver in the Linux Kernel. This issue could allow a local attacker to crash     the system due to a double-free while cleaning up vmxnet3_rq_cleanup_all, which could also lead to a     kernel information leak problem. (CVE-2023-4387)

    A NULL pointer dereference flaw was found in vmxnet3_rq_cleanup in drivers/net/vmxnet3/vmxnet3_drv.c in     the networking sub-component in vmxnet3 in the Linux Kernel. This issue may allow a local attacker with     normal user privilege to cause a denial of service due to a missing sanity check during cleanup.
    (CVE-2023-4459)

Tenable has extracted the preceding description block directly from the tested product 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 version of kernel installed on the remote host is prior to 5.10.29-27.126. It is, therefore, affected by a vulnerability as referenced in the ALAS2KERNEL-5.10-2023-030 advisory.

    An issue was discovered in fs/io_uring.c in the Linux kernel through 5.11.8. It allows attackers to cause     a denial of service (deadlock) because exit may be waiting to park a SQPOLL thread, but concurrently that     SQPOLL thread is waiting for a signal to start, aka CID-3ebba796fa25. (CVE-2021-28951)

Tenable has extracted the preceding description block directly from the tested product 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 remote Ubuntu 20.04 LTS host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-4948-1 advisory.

    Ryota Shiga discovered that the eBPF implementation in the Linux kernel did not properly verify that a BPF     program only reserved as much memory for a ring buffer as was allocated. A local attacker could use this     to cause a denial of service (system crash) or execute arbitrary code. (CVE-2021-3489)

    Manfred Paul discovered that the eBPF implementation in the Linux kernel did not properly track bounds on     bitwise operations. A local attacker could use this to cause a denial of service (system crash) or execute     arbitrary code. (CVE-2021-3490)

    Billy Jheng Bing-Jhong discovered that the io_uring implementation of the Linux kernel did not properly     enforce the MAX_RW_COUNT limit in some situations. A local attacker could use this to cause a denial of     service (system crash) or execute arbitrary code. (CVE-2021-3491)

    Kiyin () discovered that the NFC LLCP protocol implementation in the Linux kernel contained a     reference counting error. A local attacker could use this to cause a denial of service (system crash).
    (CVE-2020-25670)

    Kiyin () discovered that the NFC LLCP protocol implementation in the Linux kernel did not properly     deallocate memory in certain error situations. A local attacker could use this to cause a denial of     service (memory exhaustion). (CVE-2020-25671, CVE-2020-25672)

    It was discovered that the Xen paravirtualization backend in the Linux kernel did not properly deallocate     memory in some situations. A local attacker could use this to cause a denial of service (memory     exhaustion). (CVE-2021-28688)

    It was discovered that the io_uring subsystem in the Linux kernel contained a race condition leading to a     deadlock condition. A local attacker could use this to cause a denial of service. (CVE-2021-28951)

    John Stultz discovered that the audio driver for Qualcomm SDM845 systems in the Linux kernel did not     properly validate port ID numbers. A local attacker could use this to cause a denial of service (system     crash) or possibly execute arbitrary code. (CVE-2021-28952)

    Zygo Blaxell discovered that the btrfs file system implementation in the Linux kernel contained a race     condition during certain cloning operations. A local attacker could possibly use this to cause a denial of     service (system crash). (CVE-2021-28964)

    Vince Weaver discovered that the perf subsystem in the Linux kernel did not properly handle certain PEBS     records properly for some Intel Haswell processors. A local attacker could use this to cause a denial of     service (system crash). (CVE-2021-28971)

    It was discovered that the RPA PCI Hotplug driver implementation in the Linux kernel did not properly     handle device name writes via sysfs, leading to a buffer overflow. A privileged attacker could use this to     cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2021-28972)

    It was discovered that the Freescale Gianfar Ethernet driver for the Linux kernel did not properly handle     receive queue overrun when jumbo frames were enabled in some situations. An attacker could use this to     cause a denial of service (system crash). (CVE-2021-29264)

    It was discovered that the vDPA backend virtio driver in the Linux kernel contained a use-after-free     vulnerability. An attacker could use this to cause a denial of service (system crash) or possibly execute     arbitrary code. (CVE-2021-29266)

    It was discovered that the TIPC protocol implementation in the Linux kernel did not properly validate     passed encryption key sizes. A local attacker could use this to cause a denial of service (system crash).
    (CVE-2021-29646)

    It was discovered that the Qualcomm IPC router implementation in the Linux kernel did not properly     initialize memory passed to user space. A local attacker could use this to expose sensitive information     (kernel memory). (CVE-2021-29647)

    It was discovered that the BPF user mode driver implementation in the Linux kernel did not properly     deallocate memory in some situations. A local attacker could use this to cause a denial of service (memory     exhaustion). (CVE-2021-29649)

    It was discovered that a race condition existed in the netfilter subsystem of the Linux kernel when     replacing tables. A local attacker could use this to cause a denial of service (system crash).
    (CVE-2021-29650)

    Felix Wilhelm discovered that the KVM implementation in the Linux kernel for AMD processors contained race     conditions on nested VMCB controls. A local attacker in a guest vm could possibly use this to gain     elevated privileges. (CVE-2021-29657)

    Dan Carpenter discovered that the block device manager (dm) implementation in the Linux kernel contained a     buffer overflow in the ioctl for listing devices. A privileged local attacker could use this to cause a     denial of service (system crash). (CVE-2021-31916)

     discovered that the IEEE 1394 (Firewire) nosy packet sniffer driver in the Linux kernel did not     properly perform reference counting in some situations, leading to a use-after-free vulnerability. A local     attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code.
    (CVE-2021-3483)

Tenable has extracted the preceding description block directly from the Ubuntu 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 Fedora 32 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2021-9503fffad9 advisory.

  - An issue was discovered in the Linux kernel before 5.11.8. kernel/bpf/verifier.c performs undesirable out-     of-bounds speculation on pointer arithmetic, leading to side-channel attacks that defeat Spectre     mitigations and obtain sensitive information from kernel memory, aka CID-f232326f6966. This affects     pointer types that do not define a ptr_limit. (CVE-2020-27170)

  - An issue was discovered in the Linux kernel before 5.11.8. kernel/bpf/verifier.c has an off-by-one error     (with a resultant integer underflow) affecting out-of-bounds speculation on pointer arithmetic, leading to     side-channel attacks that defeat Spectre mitigations and obtain sensitive information from kernel memory,     aka CID-10d2bb2e6b1d. (CVE-2020-27171)

  - An issue was discovered in fs/io_uring.c in the Linux kernel through 5.11.8. It allows attackers to cause     a denial of service (deadlock) because exit may be waiting to park a SQPOLL thread, but concurrently that     SQPOLL thread is waiting for a signal to start, aka CID-3ebba796fa25. (CVE-2021-28951)

  - An issue was discovered in the Linux kernel through 5.11.8. The sound/soc/qcom/sdm845.c soundwire device     driver has a buffer overflow when an unexpected port ID number is encountered, aka CID-1c668e1c0a0f. (This     has been fixed in 5.12-rc4.) (CVE-2021-28952)

  - A race condition was discovered in get_old_root in fs/btrfs/ctree.c in the Linux kernel through 5.11.8. It     allows attackers to cause a denial of service (BUG) because of a lack of locking on an extent buffer     before a cloning operation, aka CID-dbcc7d57bffc. (CVE-2021-28964)

  - In intel_pmu_drain_pebs_nhm in arch/x86/events/intel/ds.c in the Linux kernel through 5.11.8 on some     Haswell CPUs, userspace applications (such as perf-fuzzer) can cause a system crash because the PEBS     status in a PEBS record is mishandled, aka CID-d88d05a9e0b6. (CVE-2021-28971)

  - In drivers/pci/hotplug/rpadlpar_sysfs.c in the Linux kernel through 5.11.8, the RPA PCI Hotplug driver has     a user-tolerable buffer overflow when writing a new device name to the driver from userspace, allowing     userspace to write data to the kernel stack frame directly. This occurs because add_slot_store and     remove_slot_store mishandle drc_name '\0' termination, aka CID-cc7a0bb058b8. (CVE-2021-28972)

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

The remote Fedora 33 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2021-68b0dd2373 advisory.

  - An issue was discovered in fs/io_uring.c in the Linux kernel through 5.11.8. It allows attackers to cause     a denial of service (deadlock) because exit may be waiting to park a SQPOLL thread, but concurrently that     SQPOLL thread is waiting for a signal to start, aka CID-3ebba796fa25. (CVE-2021-28951)

  - An issue was discovered in the Linux kernel through 5.11.8. The sound/soc/qcom/sdm845.c soundwire device     driver has a buffer overflow when an unexpected port ID number is encountered, aka CID-1c668e1c0a0f. (This     has been fixed in 5.12-rc4.) (CVE-2021-28952)

  - A race condition was discovered in get_old_root in fs/btrfs/ctree.c in the Linux kernel through 5.11.8. It     allows attackers to cause a denial of service (BUG) because of a lack of locking on an extent buffer     before a cloning operation, aka CID-dbcc7d57bffc. (CVE-2021-28964)

  - In intel_pmu_drain_pebs_nhm in arch/x86/events/intel/ds.c in the Linux kernel through 5.11.8 on some     Haswell CPUs, userspace applications (such as perf-fuzzer) can cause a system crash because the PEBS     status in a PEBS record is mishandled, aka CID-d88d05a9e0b6. (CVE-2021-28971)

  - In drivers/pci/hotplug/rpadlpar_sysfs.c in the Linux kernel through 5.11.8, the RPA PCI Hotplug driver has     a user-tolerable buffer overflow when writing a new device name to the driver from userspace, allowing     userspace to write data to the kernel stack frame directly. This occurs because add_slot_store and     remove_slot_store mishandle drc_name '\0' termination, aka CID-cc7a0bb058b8. (CVE-2021-28972)

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

ID	Name	Product	Family	Severity
246094	Linux Distros Unpatched Vulnerability : CVE-2021-28951	Nessus	Misc.	medium
203374	Photon OS 4.0: Linux PHSA-2021-4.0-0031	Nessus	PhotonOS Local Security Checks	medium
198268	Amazon Linux 2 : kernel (ALASKERNEL-5.10-2024-058)	Nessus	Amazon Linux Local Security Checks	high
180569	Amazon Linux 2 : kernel (ALASKERNEL-5.15-2023-023)	Nessus	Amazon Linux Local Security Checks	high
174421	Amazon Linux 2 : kernel (ALASKERNEL-5.10-2023-030)	Nessus	Amazon Linux Local Security Checks	medium
149407	Ubuntu 20.04 LTS : Linux kernel (OEM) vulnerabilities (USN-4948-1)	Nessus	Ubuntu Local Security Checks	high
148205	Fedora 32 : kernel (2021-9503fffad9)	Nessus	Fedora Local Security Checks	high
148156	Fedora 33 : kernel (2021-68b0dd2373)	Nessus	Fedora Local Security Checks	high

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CVE-2021-28951

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