QID 355617

Date Published: 2023-07-24

QID 355617: Amazon Linux Security Advisory for grub2 : ALAS2-2023-2146

a flaw was found in grub 2, where a crafted 16-bit grayscale png image may lead to an out-of-bounds write.
This flaw allows an attacker to corrupt the data on the heap portion of the grub2s memory, leading to possible code execution and the circumvention of the secure boot mechanism. (
( CVE-2021-3695) a flaw was found in grub2 when handling a png image header.
When decoding the data contained in the huffman table at the png file header, an out-of-bounds write may happen on grubs heap. (
( CVE-2021-3696) a flaw was found in grub2 when handling jpeg images.
This flaw allows an attacker to craft a malicious jpeg image, which leads to an underflow on a grub2s internal pointer, leading to a heap-based out-of-bounds write.
Secure-boot mechanisms circumvention and arbitrary code execution may also be achievable. (
( CVE-2021-3697) a flaw was found where a maliciously crafted pf2 font could lead to an out-of-bounds write in grub2.
A successful attack can lead to memory corruption and secure boot circumvention. (
( CVE-2022-2601) a flaw was found in grub2 when handling ipv4 packets.
This flaw allows an attacker to craft a malicious packet, triggering an integer underflow in grub code.
Consequently, the memory allocation for handling the packet data may be smaller than the size needed.
This issue causes an out-of-bands write during packet handling, compromising data integrity, confidentiality issues, a denial of service, and remote code execution. (

Successful exploitation of this vulnerability could lead to a securitybreach or could affect integrity, availability, and confidentiality.

  • CVSS V3 rated as Critical - 9.8 severity.
  • CVSS V2 rated as High - 6.9 severity.
  • Solution
    Please refer to Amazon advisory: ALAS2-2023-2146 for affected packages and patching details, or update with your package manager.
    Vendor References
    Software Advisories
    Advisory ID Software Component Link
    ALAS2-2023-2146 amazon linux 2 URL Logo alas.aws.amazon.com/AL2/ALAS-2023-2146.html