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CVE-2020-14309

Published: 29 July 2020

There's an issue with grub2 in all versions before 2.06 when handling squashfs filesystems containing a symbolic link with name length of UINT32 bytes in size. The name size leads to an arithmetic overflow leading to a zero-size allocation further causing a heap-based buffer overflow with attacker controlled data.

From the Ubuntu Security Team

Chris Coulson discovered that multiple integer overflows existed in GRUB2 when handling certain filesystems or font files, leading to heap-based buffer overflows. A local attacker could use these to execute arbitrary code and bypass UEFI Secure Boot restrictions.

Notes

AuthorNote
alexmurray
grub2-signed is not supported in Ubuntu 12.04 ESM (precise/esm) and so marking the priority for grub2 in this release as low

Priority

High

Cvss 3 Severity Score

5.7

Score breakdown

Status

Package Release Status
grub2
Launchpad, Ubuntu, Debian
bionic
Released (2.02-2ubuntu8.16)
focal
Released (2.04-1ubuntu26.1)
groovy Not vulnerable
(2.04-1ubuntu26.1)
hirsute Not vulnerable
(2.04-1ubuntu26.1)
precise Ignored
(end of ESM support, was needed)
trusty
Released (2.02~beta2-9ubuntu1.20)
upstream Needs triage

xenial
Released (2.02~beta2-36ubuntu3.26)
grub2-signed
Launchpad, Ubuntu, Debian
bionic
Released (1.93.18)
eoan Ignored
(reached end-of-life)
focal
Released (1.142.3)
groovy Not vulnerable
(1.147)
hirsute Not vulnerable
(1.147)
precise Does not exist

trusty
Released (1.34.22)
upstream Needs triage

xenial
Released (1.66.26)

Severity score breakdown

Parameter Value
Base score 5.7
Attack vector Local
Attack complexity High
Privileges required High
User interaction None
Scope Unchanged
Confidentiality None
Integrity impact High
Availability impact High
Vector CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:H/A:H