CVE-2021-20233

8.2HIGH

Key Information:

Vendor
Gnu
Status
Grub2
Vendor
CVE Published:
3 March 2021

Badges

👾 Exploit Exists🟡 Public PoC

Summary

A flaw was found in grub2 in versions prior to 2.06. Setparam_prefix() in the menu rendering code performs a length calculation on the assumption that expressing a quoted single quote will require 3 characters, while it actually requires 4 characters which allows an attacker to corrupt memory by one byte for each quote in the input. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

Affected Version(s)

grub2 grub 2.06

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

BootHoleFix
Created by pauljrowland

References

https://bugzilla.redhat.com/show_bug.cgi?id=1926263
x_refsource_MISC
https://lists.fedoraproject.org/archives/list/package-ann...
vendor-advisoryx_refsource_FEDORA
https://security.gentoo.org/glsa/202104-05
vendor-advisoryx_refsource_GENTOO

CVSS V3.1

Score:
8.2
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Local
Attack Complexity:
Low
Privileges Required:
High
User Interaction:
None
Scope:
Changed

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

.