A flaw was found in the KVM's AMD code for supporting the Secure Encrypted Virtualization-Encrypted State (SEV-ES). A KVM guest using SEV-ES can trigger out-of-bounds reads and writes in the host kernel via a malicious VMGEXIT for a string I/O instruction (for example, outs or ins) using the exit reason SVM_EXIT_IOIO. This issue results in a crash of the entire system or a potential guest-to-host escape scenario.

The Unity Linux 20 host has a package installed that is affected by a vulnerability as referenced in the UTSA-2026-013285 advisory.

    A flaw was found in the KVM's AMD code for supporting the Secure Encrypted Virtualization-Encrypted State     (SEV-ES). A KVM guest using SEV-ES can trigger out-of-bounds reads and writes in the host kernel via a     malicious VMGEXIT for a string I/O instruction (for example, outs or ins) using the exit reason     SVM_EXIT_IOIO. This issue results in a crash of the entire system or a potential guest-to-host escape     scenario.

Tenable has extracted the preceding description block directly from the Unity 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.

  - A flaw was found in the KVM's AMD code for supporting the Secure Encrypted Virtualization-Encrypted State     (SEV-ES). A KVM guest using SEV-ES can trigger out-of-bounds reads and writes in the host kernel via a     malicious VMGEXIT for a string I/O instruction (for example, outs or ins) using the exit reason     SVM_EXIT_IOIO. This issue results in a crash of the entire system or a potential guest-to-host escape     scenario. (CVE-2021-4093)

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

The remote Rocky Linux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the RLSA-2022:1988 advisory.

  - An out-of-bounds memory write flaw was found in the Linux kernel's joystick devices subsystem in versions     before 5.9-rc1, in the way the user calls ioctl JSIOCSBTNMAP. This flaw allows a local user to crash the     system or possibly escalate their privileges on the system. The highest threat from this vulnerability is     to confidentiality, integrity, as well as system availability. (CVE-2021-3612)

  - A use-after-free flaw was found in the Linux kernel's Bluetooth subsystem in the way user calls connect to     the socket and disconnect simultaneously due to a race condition. This flaw allows a user to crash the     system or escalate their privileges. The highest threat from this vulnerability is to confidentiality,     integrity, as well as system availability. (CVE-2021-3752)

  - A flaw was found in the Linux SCTP stack. A blind attacker may be able to kill an existing SCTP     association through invalid chunks if the attacker knows the IP-addresses and port numbers being used and     the attacker can send packets with spoofed IP addresses. (CVE-2021-3772)

  - A flaw in netfilter could allow a network-connected attacker to infer openvpn connection endpoint     information for further use in traditional network attacks. (CVE-2021-3773)

  - A memory leak flaw in the Linux kernel's hugetlbfs memory usage was found in the way the user maps some     regions of memory twice using shmget() which are aligned to PUD alignment with the fault of some of the     memory pages. A local user could use this flaw to get unauthorized access to some data. (CVE-2021-4002)

  - An information disclosure vulnerability exists in the ARM SIGPAGE functionality of Linux Kernel v5.4.66     and v5.4.54. The latest version (5.11-rc4) seems to still be vulnerable. A userland application can read     the contents of the sigpage, which can leak kernel memory contents. An attacker can read a process's     memory at a specific offset to trigger this vulnerability. This was fixed in kernel releases: 4.14.222     4.19.177 5.4.99 5.10.17 5.11 (CVE-2021-21781)

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 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2022:1988 advisory.

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

    Security Fix(es):

    * kernel: fget: check that the fd still exists after getting a ref to it (CVE-2021-4083)

    * kernel: avoid cyclic entity chains due to malformed USB descriptors (CVE-2020-0404)

    * kernel: speculation on incompletely validated data on IBM Power9 (CVE-2020-4788)

    * kernel: integer overflow in k_ascii() in drivers/tty/vt/keyboard.c (CVE-2020-13974)

    * kernel: out-of-bounds read in bpf_skb_change_head() of filter.c due to a use-after-free (CVE-2021-0941)

    * kernel: joydev: zero size passed to joydev_handle_JSIOCSBTNMAP() (CVE-2021-3612)

    * kernel: reading /proc/sysvipc/shm does not scale with large shared memory segment counts (CVE-2021-3669)

    * kernel: out-of-bound Read in qrtr_endpoint_post in net/qrtr/qrtr.c (CVE-2021-3743)

    * kernel: crypto: ccp - fix resource leaks in ccp_run_aes_gcm_cmd() (CVE-2021-3744)

    * kernel: possible use-after-free in bluetooth module (CVE-2021-3752)

    * kernel: unaccounted ipc objects in Linux kernel lead to breaking memcg limits and DoS attacks     (CVE-2021-3759)

    * kernel: DoS in ccp_run_aes_gcm_cmd() function (CVE-2021-3764)

    * kernel: sctp: Invalid chunks may be used to remotely remove existing associations (CVE-2021-3772)

    * kernel: lack of port sanity checking in natd and netfilter leads to exploit of OpenVPN clients     (CVE-2021-3773)

    * kernel: possible leak or coruption of data residing on hugetlbfs (CVE-2021-4002)

    * kernel: security regression for CVE-2018-13405 (CVE-2021-4037)

    * kernel: Buffer overwrite in decode_nfs_fh function (CVE-2021-4157)

    * kernel: cgroup: Use open-time creds and namespace for migration perm checks (CVE-2021-4197)

    * kernel: Race condition in races in sk_peer_pid and sk_peer_cred accesses (CVE-2021-4203)

    * kernel: new DNS Cache Poisoning Attack based on ICMP fragment needed packets replies (CVE-2021-20322)

    * kernel: arm: SIGPAGE information disclosure vulnerability (CVE-2021-21781)

    * hw: cpu: LFENCE/JMP Mitigation Update for CVE-2017-5715 (CVE-2021-26401)

    * kernel: Local privilege escalation due to incorrect BPF JIT branch displacement computation     (CVE-2021-29154)

    * kernel: use-after-free in hso_free_net_device() in drivers/net/usb/hso.c (CVE-2021-37159)

    * kernel: eBPF multiplication integer overflow in prealloc_elems_and_freelist() in kernel/bpf/stackmap.c     leads to out-of-bounds write (CVE-2021-41864)

    * kernel: Heap buffer overflow in firedtv driver (CVE-2021-42739)

    * kernel: ppc: kvm: allows a malicious KVM guest to crash the host (CVE-2021-43056)

    * kernel: an array-index-out-bounds in detach_capi_ctr in drivers/isdn/capi/kcapi.c (CVE-2021-43389)

    * kernel: mwifiex_usb_recv() in drivers/net/wireless/marvell/mwifiex/usb.c allows an attacker to cause DoS     via crafted USB device (CVE-2021-43976)

    * kernel: use-after-free in the TEE subsystem (CVE-2021-44733)

    * kernel: information leak in the IPv6 implementation (CVE-2021-45485)

    * kernel: information leak in the IPv4 implementation (CVE-2021-45486)

    * hw: cpu: intel: Branch History Injection (BHI) (CVE-2022-0001)

    * hw: cpu: intel: Intra-Mode BTI (CVE-2022-0002)

    * kernel: Local denial of service in bond_ipsec_add_sa (CVE-2022-0286)

    * kernel: DoS in sctp_addto_chunk in net/sctp/sm_make_chunk.c (CVE-2022-0322)

    * kernel: FUSE allows UAF reads of write() buffers, allowing theft of (partial) /etc/shadow hashes     (CVE-2022-1011)

    * kernel: use-after-free in nouveau kernel module (CVE-2020-27820)

    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.

    Additional Changes:

    For detailed information on changes in this release, see the Red Hat Enterprise Linux 8.6 Release Notes     linked from 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 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2022:1975 advisory.

    The kernel-rt packages provide the Real Time Linux Kernel, which enables fine-tuning for systems with     extremely high determinism requirements.

    Security Fix(es):

    * kernel: fget: check that the fd still exists after getting a ref to it (CVE-2021-4083)

    * kernel: avoid cyclic entity chains due to malformed USB descriptors (CVE-2020-0404)

    * kernel: integer overflow in k_ascii() in drivers/tty/vt/keyboard.c (CVE-2020-13974)

    * kernel: out-of-bounds read in bpf_skb_change_head() of filter.c due to a use-after-free (CVE-2021-0941)

    * kernel: joydev: zero size passed to joydev_handle_JSIOCSBTNMAP() (CVE-2021-3612)

    * kernel: reading /proc/sysvipc/shm does not scale with large shared memory segment counts (CVE-2021-3669)

    * kernel: out-of-bound Read in qrtr_endpoint_post in net/qrtr/qrtr.c (CVE-2021-3743)

    * kernel: crypto: ccp - fix resource leaks in ccp_run_aes_gcm_cmd() (CVE-2021-3744)

    * kernel: possible use-after-free in bluetooth module (CVE-2021-3752)

    * kernel: unaccounted ipc objects in Linux kernel lead to breaking memcg limits and DoS attacks     (CVE-2021-3759)

    * kernel: DoS in ccp_run_aes_gcm_cmd() function (CVE-2021-3764)

    * kernel: sctp: Invalid chunks may be used to remotely remove existing associations (CVE-2021-3772)

    * kernel: lack of port sanity checking in natd and netfilter leads to exploit of OpenVPN clients     (CVE-2021-3773)

    * kernel: possible leak or coruption of data residing on hugetlbfs (CVE-2021-4002)

    * kernel: security regression for CVE-2018-13405 (CVE-2021-4037)

    * kernel: Buffer overwrite in decode_nfs_fh function (CVE-2021-4157)

    * kernel: cgroup: Use open-time creds and namespace for migration perm checks (CVE-2021-4197)

    * kernel: Race condition in races in sk_peer_pid and sk_peer_cred accesses (CVE-2021-4203)

    * kernel: new DNS Cache Poisoning Attack based on ICMP fragment needed packets replies (CVE-2021-20322)

    * hw: cpu: LFENCE/JMP Mitigation Update for CVE-2017-5715 (CVE-2021-26401)

    * kernel: Local privilege escalation due to incorrect BPF JIT branch displacement computation     (CVE-2021-29154)

    * kernel: use-after-free in hso_free_net_device() in drivers/net/usb/hso.c (CVE-2021-37159)

    * kernel: eBPF multiplication integer overflow in prealloc_elems_and_freelist() in kernel/bpf/stackmap.c     leads to out-of-bounds write (CVE-2021-41864)

    * kernel: Heap buffer overflow in firedtv driver (CVE-2021-42739)

    * kernel: an array-index-out-bounds in detach_capi_ctr in drivers/isdn/capi/kcapi.c (CVE-2021-43389)

    * kernel: mwifiex_usb_recv() in drivers/net/wireless/marvell/mwifiex/usb.c allows an attacker to cause DoS     via crafted USB device (CVE-2021-43976)

    * kernel: use-after-free in the TEE subsystem (CVE-2021-44733)

    * kernel: information leak in the IPv6 implementation (CVE-2021-45485)

    * kernel: information leak in the IPv4 implementation (CVE-2021-45486)

    * hw: cpu: intel: Branch History Injection (BHI) (CVE-2022-0001)

    * hw: cpu: intel: Intra-Mode BTI (CVE-2022-0002)

    * kernel: Local denial of service in bond_ipsec_add_sa (CVE-2022-0286)

    * kernel: DoS in sctp_addto_chunk in net/sctp/sm_make_chunk.c (CVE-2022-0322)

    * kernel: FUSE allows UAF reads of write() buffers, allowing theft of (partial) /etc/shadow hashes     (CVE-2022-1011)

    * kernel: use-after-free in nouveau kernel module (CVE-2020-27820)

    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.

    Additional Changes:

    For detailed information on changes in this release, see the Red Hat Enterprise Linux 8.6 Release Notes     linked from 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 Ubuntu 20.04 LTS host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-5265-1 advisory.

    Jeremy Cline discovered a use-after-free in the nouveau graphics driver of the Linux kernel during device     removal. A privileged or physically proximate attacker could use this to cause a denial of service (system     crash). (CVE-2020-27820)

    It was discovered that the Bluetooth subsystem in the Linux kernel contained 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-2021-3640)

    Likang Luo discovered that a race condition existed in the Bluetooth subsystem of the Linux kernel,     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-2021-3752)

    It was discovered that the SCTP protocol implementation in the Linux kernel did not properly verify VTAGs     in some situations. A remote attacker could possibly use this to cause a denial of service (connection     disassociation). (CVE-2021-3772)

    It was discovered that the eBPF implementation in the Linux kernel contained a race condition around read-     only maps. A privileged attacker could use this to modify read-only maps. (CVE-2021-4001)

    It was discovered that the NFS server implementation in the Linux kernel contained an out-of-bounds write     vulnerability. A local attacker could use this to cause a denial of service (system crash) or possibly     execute arbitrary code. (CVE-2021-4090)

    Felix Wilhelm discovered that the KVM implementation in the Linux kernel did not properly handle exit     events from AMD Secure Encrypted Virtualization-Encrypted State (SEV-ES) guest VMs. An attacker in a guest     VM could use this to cause a denial of service (host kernel crash) or possibly execute arbitrary code in     the host kernel. (CVE-2021-4093)

    Lin Ma discovered that the NFC Controller Interface (NCI) implementation in the Linux kernel contained a     race condition, 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-2021-4202)

    It was discovered that the AMD Radeon GPU driver in the Linux kernel did not properly validate writes in     the debugfs file system. A privileged attacker could use this to cause a denial of service (system crash)     or possibly execute arbitrary code. (CVE-2021-42327)

    Luo Likang discovered that the FireDTV Firewire driver in the Linux kernel did not properly perform bounds     checking in some situations. A local attacker could use this to cause a denial of service (system crash)     or possibly execute arbitrary code. (CVE-2021-42739)

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.

ID	Name	Product	Family	Severity
307947	Unity Linux 20.1070e Security Update: kernel (UTSA-2026-013285)	Nessus	Unity Linux Local Security Checks	high
249026	Linux Distros Unpatched Vulnerability : CVE-2021-4093	Nessus	Misc.	high
161344	Rocky Linux 8 : kernel (RLSA-2022:1988)	Nessus	Rocky Linux Local Security Checks	critical
161047	RHEL 8 : kernel (RHSA-2022:1988)	Nessus	Red Hat Local Security Checks	critical
161034	RHEL 8 : kernel-rt (RHSA-2022:1975)	Nessus	Red Hat Local Security Checks	critical
157351	Ubuntu 20.04 LTS : Linux kernel vulnerabilities (USN-5265-1)	Nessus	Ubuntu Local Security Checks	high

Detections

Analytics

CVE-2021-4093

high

Tenable Plugins

high

high

critical

critical

critical

high