The remote Ubuntu 18.04 LTS / 20.04 LTS host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-4750-1 advisory.

  - A vulnerability was found in the Linux Kernel where the function sunkbd_reinit having been scheduled by     sunkbd_interrupt before sunkbd being freed. Though the dangling pointer is set to NULL in     sunkbd_disconnect, there is still an alias in sunkbd_reinit causing Use After Free. (CVE-2020-25669)

  - A flaw was found in the JFS filesystem code in the Linux Kernel which allows a local attacker with the     ability to set extended attributes to panic the system, causing memory corruption or escalating     privileges. The highest threat from this vulnerability is to confidentiality, integrity, as well as system     availability. (CVE-2020-27815)

  - A vulnerability was found in Linux Kernel where in the spk_ttyio_receive_buf2() function, it would     dereference spk_ttyio_synth without checking whether it is NULL or not, and may lead to a NULL-ptr deref     crash. (CVE-2020-27830)

  - An information disclosure vulnerability exists in the /proc/pid/syscall functionality of Linux Kernel 5.1     Stable and 5.4.66. More specifically, this issue has been introduced in v5.1-rc4 (commit     631b7abacd02b88f4b0795c08b54ad4fc3e7c7c0) and is still present in v5.10-rc4, so it's likely that all     versions in between are affected. An attacker can read /proc/pid/syscall to trigger this vulnerability,     which leads to the kernel leaking memory contents. (CVE-2020-28588)

  - An issue was discovered in drivers/accessibility/speakup/spk_ttyio.c in the Linux kernel through 5.9.9.
    Local attackers on systems with the speakup driver could cause a local denial of service attack, aka     CID-d41227544427. This occurs because of an invalid free when the line discipline is used more than once.
    (CVE-2020-28941)

  - An issue was discovered in Xen through 4.14.x. Some OSes (such as Linux, FreeBSD, and NetBSD) are     processing watch events using a single thread. If the events are received faster than the thread is able     to handle, they will get queued. As the queue is unbounded, a guest may be able to trigger an OOM in the     backend. All systems with a FreeBSD, Linux, or NetBSD (any version) dom0 are vulnerable. (CVE-2020-29568)

  - An issue was discovered in the Linux kernel through 5.10.1, as used with Xen through 4.14.x. The Linux     kernel PV block backend expects the kernel thread handler to reset ring->xenblkd to NULL when stopped.
    However, the handler may not have time to run if the frontend quickly toggles between the states connect     and disconnect. As a consequence, the block backend may re-use a pointer after it was freed. A misbehaving     guest can trigger a dom0 crash by continuously connecting / disconnecting a block frontend. Privilege     escalation and information leaks cannot be ruled out. This only affects systems with a Linux blkback.
    (CVE-2020-29569)

  - A locking inconsistency issue was discovered in the tty subsystem of the Linux kernel through 5.9.13.
    drivers/tty/tty_io.c and drivers/tty/tty_jobctrl.c may allow a read-after-free attack against TIOCGSID,     aka CID-c8bcd9c5be24. (CVE-2020-29660)

  - A locking issue was discovered in the tty subsystem of the Linux kernel through 5.9.13.
    drivers/tty/tty_jobctrl.c allows a use-after-free attack against TIOCSPGRP, aka CID-54ffccbf053b.
    (CVE-2020-29661)

  - A flaw was found in the Linux kernel's implementation of string matching within a packet. A privileged     user (with root or CAP_NET_ADMIN) when inserting iptables rules could insert a rule which can panic the     system. Kernel before kernel 5.5-rc1 is affected. (CVE-2021-20177)

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

Detections

Analytics

Ubuntu 18.04 LTS / 20.04 LTS : Linux kernel vulnerabilities (USN-4750-1)

high Nessus Plugin ID 148009

Version 1.7

Version 1.6

Version 1.6

Version 1.5

Version 1.7 Jan 10, 2024, 8:45 AM Detection (updated detection logic) Plugin metadata Plugin Feed: 202401100845
Version 1.6 Oct 21, 2023, 5:06 AM Detection Plugin metadata Plugin Feed: 202310210506
Version 1.6 Jan 9, 2024, 6:56 PM Detection (updated detection logic) Plugin metadata Plugin Feed: 202401091856
Version 1.5 Jan 18, 2023, 9:01 AM Logic Changes (Added support for s390x) Plugin Feed: 202301180901