Debian DSA-4843-1 : linux - security update

high Nessus Plugin ID 146052


The remote Debian host is missing a security-related update.


Several vulnerabilities have been discovered in the Linux kernel that may lead to a privilege escalation, denial of service or information leaks.

- CVE-2020-27815 A flaw was reported in the JFS filesystem code allowing a local attacker with the ability to set extended attributes to cause a denial of service.

- CVE-2020-27825 Adam 'pi3' Zabrocki reported a use-after-free flaw in the ftrace ring buffer resizing logic due to a race condition, which could result in denial of service or information leak.

- CVE-2020-27830 Shisong Qin reported a NULL pointer dereference flaw in the Speakup screen reader core driver.

- CVE-2020-28374 David Disseldorp discovered that the LIO SCSI target implementation performed insufficient checking in certain XCOPY requests. An attacker with access to a LUN and knowledge of Unit Serial Number assignments can take advantage of this flaw to read and write to any LIO backstore, regardless of the SCSI transport settings.

- CVE-2020-29568 (XSA-349) Michael Kurth and Pawel Wieczorkiewicz reported that frontends can trigger OOM in backends by updating a watched path.

- CVE-2020-29569 (XSA-350) Olivier Benjamin and Pawel Wieczorkiewicz reported a use-after-free flaw which can be triggered by a block frontend in Linux blkback. A misbehaving guest can trigger a dom0 crash by continuously connecting / disconnecting a block frontend.

- CVE-2020-29660 Jann Horn reported a locking inconsistency issue in the tty subsystem which may allow a local attacker to mount a read-after-free attack against TIOCGSID.

- CVE-2020-29661 Jann Horn reported a locking issue in the tty subsystem which can result in a use-after-free. A local attacker can take advantage of this flaw for memory corruption or privilege escalation.

- CVE-2020-36158 A buffer overflow flaw was discovered in the mwifiex WiFi driver which could result in denial of service or the execution of arbitrary code via a long SSID value.

- CVE-2021-3347 It was discovered that PI futexes have a kernel stack use-after-free during fault handling. An unprivileged user could use this flaw to crash the kernel (resulting in denial of service) or for privilege escalation.

- CVE-2021-20177 A flaw was discovered in the Linux implementation of string matching within a packet. A privileged user (with root or CAP_NET_ADMIN) can take advantage of this flaw to cause a kernel panic when inserting iptables rules.


Upgrade the linux packages.

For the stable distribution (buster), these problems have been fixed in version 4.19.171-2.

See Also

Plugin Details

Severity: High

ID: 146052

File Name: debian_DSA-4843.nasl

Version: 1.4

Type: local

Agent: unix

Published: 2/2/2021

Updated: 5/11/2022

Supported Sensors: Agentless Assessment, Frictionless Assessment Agent, Nessus Agent

Risk Information


Risk Factor: High

Score: 7.3


Risk Factor: High

Base Score: 7.2

Temporal Score: 5.6

Vector: CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C

CVSS Score Source: CVE-2021-3347


Risk Factor: High

Base Score: 8.8

Temporal Score: 7.9

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:debian:debian_linux:linux, cpe:/o:debian:debian_linux:10.0

Required KB Items: Host/local_checks_enabled, Host/Debian/release, Host/Debian/dpkg-l

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 2/1/2021

Vulnerability Publication Date: 12/9/2020

Reference Information

CVE: CVE-2020-27815, CVE-2020-27825, CVE-2020-27830, CVE-2020-28374, CVE-2020-29568, CVE-2020-29569, CVE-2020-29660, CVE-2020-29661, CVE-2020-36158, CVE-2021-20177, CVE-2021-3347

DSA: 4843