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Vulnerability of Linux kernel: use after free via try_merge_free_space

Synthesis of the vulnerability 

An attacker can force the usage of a freed memory area via try_merge_free_space() of the Linux kernel, in order to trigger a denial of service, and possibly to run code.
Impacted products: Debian, Linux, Slackware, Ubuntu.
Severity of this bulletin: 2/4.
Creation date: 09/12/2019.
Références of this threat: CERTFR-2020-AVI-614, CVE-2019-19448, DLA-2385-1, SSA:2020-295-01, USN-4578-1, VIGILANCE-VUL-31095.

Description of the vulnerability 

An attacker can force the usage of a freed memory area via try_merge_free_space() of the Linux kernel, in order to trigger a denial of service, and possibly to run code.
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This computer vulnerability note impacts software or systems such as Debian, Linux, Slackware, Ubuntu.

Our Vigil@nce team determined that the severity of this computer vulnerability announce is medium.

The trust level is of type confirmed by the editor, with an origin of physical access.

A proof of concept or an attack tool is available, so your teams have to process this alert. An attacker with a technician ability can exploit this cybersecurity announce.

Solutions for this threat 

Linux kernel: version 5.8.3.
The version 5.8.3 is fixed:
  https://cdn.kernel.org/pub/linux/kernel/v5.x/

Linux kernel: version 5.7.17.
The version 5.7.17 is fixed:
  https://cdn.kernel.org/pub/linux/kernel/v5.x/

Linux kernel: version 5.4.60.
The version 5.4.60 is fixed:
  https://cdn.kernel.org/pub/linux/kernel/v5.x/

Linux kernel: version 4.19.141.
The version 4.19.141 is fixed:
  https://cdn.kernel.org/pub/linux/kernel/v4.x/

Linux kernel: version 4.14.194.
The version 4.14.194 is fixed:
  https://cdn.kernel.org/pub/linux/kernel/v4.x/

Linux kernel: version 4.9.233.
The version 4.9.233 is fixed:
  https://cdn.kernel.org/pub/linux/kernel/v4.x/

Linux kernel: version 4.4.233.
The version 4.4.233 is fixed:
  https://cdn.kernel.org/pub/linux/kernel/v4.x/

Linux kernel: patch for try_merge_free_space.
A patch is indicated in information sources.

Debian 9: new linux-4.19 packages.
New packages are available:
  Debian 9: linux-4.19 4.19.146-1~deb9u1

Slackware 14.2: new kernel packages (22/10/2020).
New packages are available:
  Slackware 14.2: kernel 4.4.240-i586-1

Ubuntu: new linux-image-4.15.0 packages.
New packages are available:
  Ubuntu 14.04 ESM: linux-image-azure 4.15.0.1098.74
  Ubuntu 16.04 LTS: linux-image-generic-hwe-16.04 4.15.0.120.121
  Ubuntu 18.04 LTS: linux-image-generic 4.15.0.121.108
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Computer vulnerabilities tracking service 

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