An update of the linux package has been released.

The remote Ubuntu 21.04 host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-4997-2 advisory.

    USN-4997-1 fixed vulnerabilities in the Linux kernel for Ubuntu 21.04. This update provides the     corresponding updates for the Linux KVM kernel for Ubuntu 21.04.

    Norbert Slusarek discovered a race condition in the CAN BCM networking protocol of the Linux kernel     leading to multiple use-after-free vulnerabilities. A local attacker could use this issue to execute     arbitrary code. (CVE-2021-3609)

    Piotr Krysiuk discovered that the eBPF implementation in the Linux kernel did not properly enforce limits     for pointer operations. A local attacker could use this to cause a denial of service (system crash) or     possibly execute arbitrary code. (CVE-2021-33200)

    Mathy Vanhoef discovered that the Linux kernels WiFi implementation did not properly clear received     fragments from memory in some situations. A physically proximate attacker could possibly use this issue to     inject packets or expose sensitive information. (CVE-2020-24586)

    Mathy Vanhoef discovered that the Linux kernels WiFi implementation incorrectly handled encrypted     fragments. A physically proximate attacker could possibly use this issue to decrypt fragments.
    (CVE-2020-24587)

    Mathy Vanhoef discovered that the Linux kernels WiFi implementation incorrectly handled certain     malformed frames. If a user were tricked into connecting to a malicious server, a physically proximate     attacker could use this issue to inject packets. (CVE-2020-24588)

    Mathy Vanhoef discovered that the Linux kernels WiFi implementation incorrectly handled EAPOL frames     from unauthenticated senders. A physically proximate attacker could inject malicious packets to cause a     denial of service (system crash). (CVE-2020-26139)

    Mathy Vanhoef discovered that the Linux kernels WiFi implementation did not properly verify certain     fragmented frames. A physically proximate attacker could possibly use this issue to inject or decrypt     packets. (CVE-2020-26141)

    Mathy Vanhoef discovered that the Linux kernels WiFi implementation accepted plaintext fragments in     certain situations. A physically proximate attacker could use this issue to inject packets.
    (CVE-2020-26145)

    Mathy Vanhoef discovered that the Linux kernels WiFi implementation could reassemble mixed encrypted     and plaintext fragments. A physically proximate attacker could possibly use this issue to inject packets     or exfiltrate selected fragments. (CVE-2020-26147)

    Or Cohen discovered that the SCTP implementation in the Linux kernel contained a race condition in some     situations, leading to a use-after-free condition. A local attacker could use this to cause a denial of     service (system crash) or possibly execute arbitrary code. (CVE-2021-23133)

    Or Cohen and Nadav Markus discovered a use-after-free vulnerability in the nfc implementation in the Linux     kernel. A privileged local attacker could use this issue to cause a denial of service (system crash) or     possibly execute arbitrary code. (CVE-2021-23134)

    Manfred Paul discovered that the extended Berkeley Packet Filter (eBPF) implementation in the Linux kernel     contained an out-of-bounds vulnerability. A local attacker could use this issue to execute arbitrary code.
    (CVE-2021-31440)

    Piotr Krysiuk discovered that the eBPF implementation in the Linux kernel did not properly prevent     speculative loads in certain situations. A local attacker could use this to expose sensitive information     (kernel memory). (CVE-2021-31829)

    It was discovered that a race condition in the kernel Bluetooth subsystem could lead to use-after-free of     slab objects. An attacker could use this issue to possibly execute arbitrary code. (CVE-2021-32399)

    It was discovered that a use-after-free existed in the Bluetooth HCI driver of the Linux kernel. A local     attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code.
    (CVE-2021-33034)

    It was discovered that an out-of-bounds (OOB) memory access flaw existed in the f2fs module of the Linux     kernel. A local attacker could use this issue to cause a denial of service (system crash). (CVE-2021-3506)

    Mathias Krause discovered that a null pointer dereference existed in the Nitro Enclaves kernel driver of     the Linux kernel. A local attacker could use this issue to cause a denial of service or possibly execute     arbitrary code. (CVE-2021-3543)

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 Redhat Enterprise Linux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2021:4140 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: out-of-bounds reads in pinctrl subsystem. (CVE-2020-0427)
    * kernel: Improper input validation in some Intel(R) Ethernet E810 Adapter drivers (CVE-2020-24502)
    * kernel: Insufficient access control in some Intel(R) Ethernet E810 Adapter drivers (CVE-2020-24503)
    * kernel: Uncontrolled resource consumption in some Intel(R) Ethernet E810 Adapter drivers     (CVE-2020-24504)
    * kernel: Fragmentation cache not cleared on reconnection (CVE-2020-24586)
    * kernel: Reassembling fragments encrypted under different keys (CVE-2020-24587)
    * kernel: wifi frame payload being parsed incorrectly as an L2 frame (CVE-2020-24588)
    * kernel: Forwarding EAPOL from unauthenticated wifi client (CVE-2020-26139)
    * kernel: accepting plaintext data frames in protected networks (CVE-2020-26140)
    * kernel: not verifying TKIP MIC of fragmented frames (CVE-2020-26141)
    * kernel: accepting fragmented plaintext frames in protected networks (CVE-2020-26143)
    * kernel: accepting unencrypted A-MSDU frames that start with RFC1042 header (CVE-2020-26144)
    * kernel: accepting plaintext broadcast fragments as full frames (CVE-2020-26145)
    * kernel: locking inconsistency in tty_io.c and tty_jobctrl.c can lead to a read-after-free     (CVE-2020-29660)
    * kernel: buffer overflow in mwifiex_cmd_802_11_ad_hoc_start function via a long SSID value     (CVE-2020-36158)
    * kernel: slab out-of-bounds read in hci_extended_inquiry_result_evt() (CVE-2020-36386)
    * kernel: Improper access control in BlueZ may allow information disclosure vulnerability. (CVE-2021-0129)
    * kernel: Use-after-free in ndb_queue_rq() (CVE-2021-3348)
    * kernel: Linux kernel eBPF RINGBUF map oversized allocation (CVE-2021-3489)
    * kernel: double free in bluetooth subsystem when the HCI device initialization fails (CVE-2021-3564)
    * kernel: use-after-free in function hci_sock_bound_ioctl() (CVE-2021-3573)
    * kernel: eBPF 32-bit source register truncation on div/mod (CVE-2021-3600)
    * kernel: DoS in rb_per_cpu_empty() (CVE-2021-3679)
    * kernel: overlayfs: Mounting overlayfs inside an unprivileged user namespace can reveal files     (CVE-2021-3732)
    * kernel: heap overflow in __cgroup_bpf_run_filter_getsockopt() (CVE-2021-20194)
    * kernel: Race condition in sctp_destroy_sock list_del (CVE-2021-23133)
    * kernel: fuse: stall on CPU can occur because a retry loop continually finds the same bad inode     (CVE-2021-28950)
    * kernel: System crash in intel_pmu_drain_pebs_nhm (CVE-2021-28971)
    * kernel: protection for sequences of pointer arithmetic operations against speculatively out-of-bounds     loads can be bypassed to leak content of kernel memory (CVE-2021-29155)
    * kernel: improper input validation in tipc_nl_retrieve_key function (CVE-2021-29646)
    * kernel: lack a full memory barrier upon the assignment of a new table value in x_tables.h may lead to     DoS (CVE-2021-29650)
    * kernel: local escalation of privileges in handling of eBPF programs (CVE-2021-31440)
    * kernel: protection of stack pointer against speculative pointer arithmetic can be bypassed to leak     content of kernel memory (CVE-2021-31829)
    * kernel: out-of-bounds reads and writes due to enforcing incorrect limits for pointer arithmetic     operations by BPF verifier (CVE-2021-33200)
    * kernel: reassembling encrypted fragments with non-consecutive packet numbers (CVE-2020-26146)
    * kernel: reassembling mixed encrypted/plaintext fragments (CVE-2020-26147)
    * kernel: the copy-on-write implementation can grant unintended write access because of a race condition     in a THP mapcount check (CVE-2020-29368)
    * kernel: flowtable list del corruption with kernel BUG (CVE-2021-3635)
    * kernel: NULL pointer dereference in llsec_key_alloc()  (CVE-2021-3659)
    * kernel: setsockopt System Call Untrusted Pointer Dereference Information Disclosure (CVE-2021-20239)
    * kernel: out of bounds array access in drivers/md/dm-ioctl.c (CVE-2021-31916)

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

  - This vulnerability allows local attackers to escalate privileges on affected installations of Linux Kernel     5.11.15. An attacker must first obtain the ability to execute low-privileged code on the target system in     order to exploit this vulnerability. The specific flaw exists within the handling of eBPF programs. The     issue results from the lack of proper validation of user-supplied eBPF programs prior to executing them.
    An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the     context of the kernel. Was ZDI-CAN-13661. (CVE-2021-31440)

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

The Unity Linux 20 host has a package installed that is affected by a vulnerability as referenced in the UTSA-2025-414612 advisory.

    This vulnerability allows local attackers to escalate privileges on affected installations of Linux Kernel     5.11.15. An attacker must first obtain the ability to execute low-privileged code on the target system in     order to exploit this vulnerability. The specific flaw exists within the handling of eBPF programs. The     issue results from the lack of proper validation of user-supplied eBPF programs prior to executing them.
    An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the     context of the kernel. Was ZDI-CAN-13661.

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 remote Ubuntu 21.04 host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-4997-1 advisory.

    Norbert Slusarek discovered a race condition in the CAN BCM networking protocol of the Linux kernel     leading to multiple use-after-free vulnerabilities. A local attacker could use this issue to execute     arbitrary code. (CVE-2021-3609)

    Piotr Krysiuk discovered that the eBPF implementation in the Linux kernel did not properly enforce limits     for pointer operations. A local attacker could use this to cause a denial of service (system crash) or     possibly execute arbitrary code. (CVE-2021-33200)

    Mathy Vanhoef discovered that the Linux kernels WiFi implementation did not properly clear received     fragments from memory in some situations. A physically proximate attacker could possibly use this issue to     inject packets or expose sensitive information. (CVE-2020-24586)

    Mathy Vanhoef discovered that the Linux kernels WiFi implementation incorrectly handled encrypted     fragments. A physically proximate attacker could possibly use this issue to decrypt fragments.
    (CVE-2020-24587)

    Mathy Vanhoef discovered that the Linux kernels WiFi implementation incorrectly handled certain     malformed frames. If a user were tricked into connecting to a malicious server, a physically proximate     attacker could use this issue to inject packets. (CVE-2020-24588)

    Mathy Vanhoef discovered that the Linux kernels WiFi implementation incorrectly handled EAPOL frames     from unauthenticated senders. A physically proximate attacker could inject malicious packets to cause a     denial of service (system crash). (CVE-2020-26139)

    Mathy Vanhoef discovered that the Linux kernels WiFi implementation did not properly verify certain     fragmented frames. A physically proximate attacker could possibly use this issue to inject or decrypt     packets. (CVE-2020-26141)

    Mathy Vanhoef discovered that the Linux kernels WiFi implementation accepted plaintext fragments in     certain situations. A physically proximate attacker could use this issue to inject packets.
    (CVE-2020-26145)

    Mathy Vanhoef discovered that the Linux kernels WiFi implementation could reassemble mixed encrypted     and plaintext fragments. A physically proximate attacker could possibly use this issue to inject packets     or exfiltrate selected fragments. (CVE-2020-26147)

    Or Cohen discovered that the SCTP implementation in the Linux kernel contained a race condition in some     situations, leading to a use-after-free condition. A local attacker could use this to cause a denial of     service (system crash) or possibly execute arbitrary code. (CVE-2021-23133)

    Or Cohen and Nadav Markus discovered a use-after-free vulnerability in the nfc implementation in the Linux     kernel. A privileged local attacker could use this issue to cause a denial of service (system crash) or     possibly execute arbitrary code. (CVE-2021-23134)

    Manfred Paul discovered that the extended Berkeley Packet Filter (eBPF) implementation in the Linux kernel     contained an out-of-bounds vulnerability. A local attacker could use this issue to execute arbitrary code.
    (CVE-2021-31440)

    Piotr Krysiuk discovered that the eBPF implementation in the Linux kernel did not properly prevent     speculative loads in certain situations. A local attacker could use this to expose sensitive information     (kernel memory). (CVE-2021-31829)

    It was discovered that a race condition in the kernel Bluetooth subsystem could lead to use-after-free of     slab objects. An attacker could use this issue to possibly execute arbitrary code. (CVE-2021-32399)

    It was discovered that a use-after-free existed in the Bluetooth HCI driver of the Linux kernel. A local     attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code.
    (CVE-2021-33034)

    It was discovered that an out-of-bounds (OOB) memory access flaw existed in the f2fs module of the Linux     kernel. A local attacker could use this issue to cause a denial of service (system crash). (CVE-2021-3506)

    Mathias Krause discovered that a null pointer dereference existed in the Nitro Enclaves kernel driver of     the Linux kernel. A local attacker could use this issue to cause a denial of service or possibly execute     arbitrary code. (CVE-2021-3543)

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	Published	Updated	Severity
150921	Photon OS 4.0: Linux PHSA-2021-4.0-0047	Nessus	PhotonOS Local Security Checks	6/21/2021	10/16/2025	high
153127	Ubuntu 21.04 : Linux kernel (KVM) vulnerabilities (USN-4997-2)	Nessus	Ubuntu Local Security Checks	9/8/2021	8/27/2024	high
155172	RHEL 8 : kernel-rt (RHSA-2021:4140)	Nessus	Red Hat Local Security Checks	11/11/2021	11/7/2024	high
247215	Linux Distros Unpatched Vulnerability : CVE-2021-31440	Nessus	Misc.	8/10/2025	7/17/2026	high
267086	Unity Linux 20.1070e Security Update: kernel (UTSA-2025-414612)	Nessus	Unity Linux Local Security Checks	10/7/2025	10/15/2025	high
150953	Ubuntu 21.04 : Linux kernel vulnerabilities (USN-4997-1)	Nessus	Ubuntu Local Security Checks	6/23/2021	8/28/2024	high

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