A linux kernel security update has been released for Debian GNU/Linux 10 to address several vulnerabilities that may lead to a privilege escalation, denial of service or information leaks.

DSA 4843-1: linux security update

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Debian Security Advisory DSA-4843-1 security@debian.org
  https://www.debian.org/security/ Salvatore Bonaccorso
February 01, 2021   https://www.debian.org/security/faq
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Package : linux
CVE ID : 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-2021-3347 CVE-2021-20177
Debian Bug : 970736 972345 977048 977615

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.

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

We recommend that you upgrade your linux packages.

For the detailed security status of linux please refer to its security
tracker page at:
  https://security-tracker.debian.org/tracker/linux

Further information about Debian Security Advisories, how to apply
these updates to your system and frequently asked questions can be
found at:   https://www.debian.org/security/