Grub2
CVE-2021-20225
MEDIUM
Vulnerability Assessment
| Weakness |
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Bounds checking, write limits
MITRE ATT&CK
2 techniques across 2 tactics: Execution, Privilege Escalation The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS score of 6.7 (MEDIUM). Attack characteristics: local attack vector, low complexity, high privileges required, no user interaction not required. |
| Exploit ScenarioDerived | A local attacker with access to the system could write data beyond allocated buffer boundaries leading to code execution or crashes. |
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Alert meAnalysisAI
A flaw was found in grub2 in versions prior to 2.06. Rated medium severity (CVSS 6.7), this vulnerability is low attack complexity. No vendor patch available.
RemediationAI
No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Validate write boundaries, use memory-safe languages, enable compiler protections (ASLR, stack canaries).
Affects your stack
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Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
This vulnerability is classified as Out-of-bounds Write (CWE-787), which allows attackers to write data beyond allocated buffer boundaries leading to code execution or crashes. A flaw was found in grub2 in versions prior to 2.06. The option parser allows an attacker to write past the end of a heap-allocated buffer by calling certain commands with a large number of specific short forms of options. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability. Affected products include: Gnu Grub2, Redhat Enterprise Linux, Redhat Enterprise Linux Server Aus, Redhat Enterprise Linux Server Eus, Redhat Enterprise Linux Server Tus. Version information: prior to 2.06..
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionNVD
A flaw was found in grub2 in versions prior to 2.06. The option parser allows an attacker to write past the end of a heap-allocated buffer by calling certain commands with a large number of specific short forms of options. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
Threat Intelligence Overview
NVD
CVE.org
EPSS
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.
Memory corruption occurs when a program writes data beyond the boundaries of allocated memory regions or accesses memory in unintended ways, violating the integrity of the process's address space.
Affected Products (CPE)NVD
Multiple integer underflows in Grub2 1.98 through 2.02 allow physically proximate attackers to bypass authentication, ob
An out-of-bounds write flaw was found in grub2's NTFS filesystem driver. Rated high severity (CVSS 7.8), this vulnerabil
GRUB2 does not call the module fini functions on exit, leading to Debian/Ubuntu's peimage GRUB2 module leaving UEFI syst
Integer overflows were discovered in the functions grub_cmd_initrd and grub_initrd_init in the efilinux component of GRU
GNU GRUB (aka GRUB2) through 2.12 has a heap-based buffer overflow in fs/hfs.c via crafted sblock data in an HFS filesys
An out-of-bounds read flaw was found on grub2's NTFS filesystem driver. Rated medium severity (CVSS 4.6), this vulnerabi
A buffer overflow was found in grub_font_construct_glyph(). Rated high severity (CVSS 8.6), this vulnerability is no aut
A flaw was found in grub2 in versions prior to 2.06. Rated high severity (CVSS 8.2), this vulnerability is low attack co
A flaw was found in grub2, prior to version 2.06. Rated high severity (CVSS 8.2), this vulnerability is low attack compl
A flaw was found in grub2. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. No vendor patch
A flaw was found in the HFS filesystem. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. No
When reading data from a hfs filesystem, grub's hfs filesystem module uses user-controlled parameters from the filesyste
GitHub PoC
Exploit-DB