CVE-2021-3695

A crafted 16-bit grayscale PNG image may lead to a out-of-bounds write in the heap area. An attacker may take advantage of that to cause heap data corruption or eventually arbitrary code execution and circumvent secure boot protections. This issue has a high complexity to be exploited as an attacker needs to perform some triage over the heap layout to achieve signifcant results, also the values written into the memory are repeated three times in a row making difficult to produce valid payloads. This flaw affects grub2 versions prior grub-2.12.

A crafted 16-bit grayscale PNG image may lead to a out-of-bounds write in the heap area. An attacker may take advantage of that to cause heap data corruption or eventually arbitrary code execution and circumvent secure boot protections. This issue has a high complexity to be exploited as an attacker needs to perform some triage over the heap layout to achieve signifcant results, also the values written into the memory are repeated three times in a row making difficult to produce valid payloads. This flaw affects grub2 versions prior grub-2.12.

GNU GRUB is a Multiboot boot loader. It was derived from GRUB, the GRand Unified Bootloader, which was originally designed and implemented by Erich Stefan Boleyn.

Security Fix(es):

A flaw was found in grub2 when handling split HTTP headers. While processing a split HTTP header, grub2 wrongly advances its control pointer to the internal buffer by one position, which can lead to an out-of-bounds write. This flaw allows an attacker to leverage this issue by crafting a malicious set of HTTP packages making grub2 corrupt its internal memory metadata structure. This leads to data integrity and confidentiality issues or forces grub to crash, resulting in a denial of service attack.(CVE-2022-28734)

A use-after-free vulnerability was found on grub2's chainloader command. This flaw allows an attacker to gain access to restricted data or cause arbitrary code execution if they can establish control from grub's memory allocation pattern.(CVE-2022-28736)

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 grub2's 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 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 grub's heap.(CVE-2021-3696)

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.(CVE-2022-28733)

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 grub2's memory, leading to possible code execution and the circumvention of the secure boot mechanism.(CVE-2021-3695)

A flaw was found in grub2. The shim_lock verifier from grub2 allows non-kernel files to be loaded when secure boot is enabled, giving the possibility of unverified code or modules to be loaded when it should not be allowed. (CVE-2022-28735)

The grub2 packages provide version 2 of the Grand Unified Boot Loader (GRUB), a highly configurable and customizable boot loader with modular architecture. The packages support a variety of kernel formats, file systems, computer architectures, and hardware devices.

The shim package contains a first-stage UEFI boot loader that handles chaining to a trusted full boot loader under secure boot environments.

Security Fix(es):

• grub2: Integer underflow in grub_net_recv_ip4_packets (CVE-2022-28733)

• grub2: Crafted PNG grayscale images may lead to out-of-bounds write in heap (CVE-2021-3695)

• grub2: Crafted PNG image may lead to out-of-bound write during huffman table handling (CVE-2021-3696)

• grub2: Crafted JPEG image can lead to buffer underflow write in the heap (CVE-2021-3697)

• grub2: Out-of-bound write when handling split HTTP headers (CVE-2022-28734)

• grub2: shim_lock verifier allows non-kernel files to be loaded (CVE-2022-28735)

• grub2: use-after-free in grub_cmd_chainloader() (CVE-2022-28736)

• shim: Buffer overflow when loading crafted EFI images (CVE-2022-28737)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

The grub2 packages provide version 2 of the Grand Unified Boot Loader (GRUB), a highly configurable and customizable boot loader with modular architecture. The packages support a variety of kernel formats, file systems, computer architectures, and hardware devices.

The shim package contains a first-stage UEFI boot loader that handles chaining to a trusted full boot loader under secure boot environments.

Security Fix(es):

• grub2: Integer underflow in grub_net_recv_ip4_packets (CVE-2022-28733)

• grub2: Crafted PNG grayscale images may lead to out-of-bounds write in heap (CVE-2021-3695)

• grub2: Crafted PNG image may lead to out-of-bound write during huffman table handling (CVE-2021-3696)

• grub2: Crafted JPEG image can lead to buffer underflow write in the heap (CVE-2021-3697)

• grub2: Out-of-bound write when handling split HTTP headers (CVE-2022-28734)

• grub2: shim_lock verifier allows non-kernel files to be loaded (CVE-2022-28735)

• grub2: use-after-free in grub_cmd_chainloader() (CVE-2022-28736)

• shim: Buffer overflow when loading crafted EFI images (CVE-2022-28737)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

A crafted 16-bit grayscale PNG image may lead to a out-of-bounds write in the heap area. An attacker may take advantage of that to cause heap data corruption or eventually arbitrary code execution and circumvent secure boot protections. This issue has a high complexity to be exploited as an attacker needs to perform some triage over the heap layout to achieve signifcant results, also the values written into the memory are repeated three times in a row making difficult to produce valid payloads. This flaw affects grub2 versions prior grub-2.12.

The grub2 packages provide version 2 of the Grand Unified Boot Loader (GRUB), a highly configurable and customizable boot loader with modular architecture. The packages support a variety of kernel formats, file systems, computer architectures, and hardware devices. The shim package contains a first-stage UEFI boot loader that handles chaining to a trusted full boot loader under secure boot environments. Security Fix(es):

• grub2: Integer underflow in grub_net_recv_ip4_packets (CVE-2022-28733)
• grub2: Crafted PNG grayscale images may lead to out-of-bounds write in heap (CVE-2021-3695)
• grub2: Crafted PNG image may lead to out-of-bound write during huffman table handling (CVE-2021-3696)
• grub2: Crafted JPEG image can lead to buffer underflow write in the heap (CVE-2021-3697)
• grub2: Out-of-bound write when handling split HTTP headers (CVE-2022-28734)
• grub2: shim_lock verifier allows non-kernel files to be loaded (CVE-2022-28735)
• grub2: use-after-free in grub_cmd_chainloader() (CVE-2022-28736)
• shim: Buffer overflow when loading crafted EFI images (CVE-2022-28737) For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

The grub2 packages provide version 2 of the Grand Unified Boot Loader (GRUB), a highly configurable and customizable boot loader with modular architecture. The packages support a variety of kernel formats, file systems, computer architectures, and hardware devices. The shim package contains a first-stage UEFI boot loader that handles chaining to a trusted full boot loader under secure boot environments. Security Fix(es):

• grub2: Integer underflow in grub_net_recv_ip4_packets (CVE-2022-28733)
• grub2: Crafted PNG grayscale images may lead to out-of-bounds write in heap (CVE-2021-3695)
• grub2: Crafted PNG image may lead to out-of-bound write during huffman table handling (CVE-2021-3696)
• grub2: Crafted JPEG image can lead to buffer underflow write in the heap (CVE-2021-3697)
• grub2: Out-of-bound write when handling split HTTP headers (CVE-2022-28734)
• grub2: shim_lock verifier allows non-kernel files to be loaded (CVE-2022-28735)
• grub2: use-after-free in grub_cmd_chainloader() (CVE-2022-28736)
• shim: Buffer overflow when loading crafted EFI images (CVE-2022-28737) For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

• CVE-2021-3981: Fix default privileges of grub.cfg file
• CVE-2022-28736: Fix use-after-free bug when grub_cmd_chainloader is executed more than once before a boot attempt is performed.
• CVE-2021-3695: Drop greyscale support to fix heap out-of-bounds write
• CVE-2021-3696: Fix out of range insertion into huffman table
• CVE-2021-3697: Fix integer undeflow which resulted in wild pointer write
• CVE-2022-28733: Fix integer underflow which resulted in subsequent unpleasantness
• CVE-2022-28734: Fix erros in handling of split http headers

• CVE-2021-3981: Fix default privileges of grub.cfg file
• CVE-2022-28736: Fix use-after-free bug when grub_cmd_chainloader is executed more than once before a boot attempt is performed.
• CVE-2021-3695: Drop greyscale support to fix heap out-of-bounds write
• CVE-2021-3696: Fix out of range insertion into huffman table
• CVE-2021-3697: Fix integer undeflow which resulted in wild pointer write
• CVE-2022-28733: Fix integer underflow which resulted in subsequent unpleasantness
• CVE-2022-28734: Fix erros in handling of split http headers

• Fix package version number
• Use CloudLinux vendor cert
• Make this package installable only on a system having Cloudlinux signed components: grub2 and kernel
• Add patches from centos-8.5 ELS:
• CVE-2021-3695: out-of-bounds write in the heap area by a crafted 16-bit grayscale PNG image
• CVE-2021-3696: a heap out-of-bounds during the handling of Huffman tables in the PNG reader
• CVE-2021-3697: allowing user-controlled data to be written in heap by a crafted JPEG image
• CVE-2022-2601: possible circumventing of the secure boot mechanism by a malicious crafted pf2 font
• CVE-2022-28733: possible write past the end of the buffer because of integer underflow in grub_net_recv_ip4_packets()
• CVE-2022-28734: out-of-bounds write when handling split HTTP headers
• CVE-2022-28736: use-after-free vulnerability in grub_cmd_chainloader()
• CVE-2022-3775: out-of-bounds write into grub2’s heap because of lack of proper validation of glyph’s width and height
• CVE-2023-4692: out-of-bounds write in grub2’s NTFS filesystem driver
• The following CVEs were fixed by previous patches additionally:
• CVE-2020-15706: a race condition in grub_script_function_create() leading to a use-after-free vulnerability
• CVE-2020-15707: integer overflows in efilinux leading to a heap-based buffer overflow
• A number of upstream fixes backported including:
• CVE-2024-1048: a flaw that may result in filesystem running out of free inodes or blocks

These are all security issues fixed in the grub2-2.06-25.1 package on the GA media of openSUSE Tumbleweed.

This update for grub2 fixes the following issues:

This update provides security fixes and hardenings for Boothole 3 / Boothole 2022 (bsc#1198581)

• CVE-2021-3695: Fixed that a crafted PNG grayscale image could lead to out-of-bounds write in heap (bsc#1191184)

• CVE-2021-3696: Fixed that a crafted PNG image could lead to out-of-bound write during huffman table handling (bsc#1191185)

• CVE-2021-3697: Fixed that a crafted JPEG image could lead to buffer underflow write in the heap (bsc#1191186)

• CVE-2022-28733: Fixed fragmentation math in net/ip (bsc#1198460)

• CVE-2022-28734: Fixed an out-of-bound write for split http headers (bsc#1198493)

• CVE-2022-28735: Fixed some verifier framework changes (bsc#1198495)

• CVE-2022-28736: Fixed a use-after-free in chainloader command (bsc#1198496)

• Update SBAT security contact (bsc#1193282)

• Bump grub's SBAT generation to 2

• Use boot disks in OpenFirmware, fixing regression caused when the root LV is completely in the boot LUN (bsc#1197948)

This update for grub2 fixes the following issues:

Security fixes and hardenings for boothole 3 / boothole 2022 (bsc#1198581)

• CVE-2021-3695: Fixed that a crafted PNG grayscale image could lead to out-of-bounds write in heap (bsc#1191184)

• CVE-2021-3696: Fixed that a crafted PNG image could lead to out-of-bound write during huffman table handling (bsc#1191185)

• CVE-2021-3697: Fixed that a crafted JPEG image could lead to buffer underflow write in the heap (bsc#1191186)

• CVE-2022-28733: Fixed fragmentation math in net/ip (bsc#1198460)

• CVE-2022-28734: Fixed an out-of-bound write for split http headers (bsc#1198493)

• CVE-2022-28736: Fixed a use-after-free in chainloader command (bsc#1198496)

• Update SBAT security contact (bsc#1193282)

• Bump grub's SBAT generation to 2

This update for grub2 fixes the following issues:

Security fixes and hardenings for boothole 3 / boothole 2022 (bsc#1198581)

• CVE-2021-3695: Fixed that a crafted PNG grayscale image could lead to out-of-bounds write in heap (bsc#1191184)

• CVE-2021-3696: Fixed that a crafted PNG image could lead to out-of-bound write during huffman table handling (bsc#1191185)

• CVE-2021-3697: Fixed that a crafted JPEG image could lead to buffer underflow write in the heap (bsc#1191186)

• CVE-2022-28733: Fixed fragmentation math in net/ip (bsc#1198460)

• CVE-2022-28734: Fixed an out-of-bound write for split http headers (bsc#1198493)

• CVE-2022-28736: Fixed a use-after-free in chainloader command (bsc#1198496)

• Update SBAT security contact (bsc#1193282)

• Bump grub's SBAT generation to 2

• Use boot disks in OpenFirmware, fixing regression caused when the root LV is completely in the boot LUN (bsc#1197948)

This update for grub2 fixes the following issues:

Security fixes and hardenings for boothole 3 / boothole 2022 (bsc#1198581)

• CVE-2021-3695: Fixed that a crafted PNG grayscale image could lead to out-of-bounds write in heap (bsc#1191184)

• CVE-2021-3696: Fixed that a crafted PNG image could lead to out-of-bound write during huffman table handling (bsc#1191185)

• CVE-2021-3697: Fixed that a crafted JPEG image could lead to buffer underflow write in the heap (bsc#1191186)

• CVE-2022-28733: Fixed fragmentation math in net/ip (bsc#1198460)

• CVE-2022-28734: Fixed an out-of-bound write for split http headers (bsc#1198493)

• CVE-2022-28736: Fixed a use-after-free in chainloader command (bsc#1198496)

• Update SBAT security contact (bsc#1193282)

• Bump grub's SBAT generation to 2

• Use boot disks in OpenFirmware, fixing regression caused when the root LV is completely in the boot LUN (bsc#1197948)

This update for grub2 fixes the following issues:

Security fixes and hardenings for boothole 3 / boothole 2022 (bsc#1198581)

• CVE-2021-3695: Fixed that a crafted PNG grayscale image could lead to out-of-bounds write in heap (bsc#1191184)
• CVE-2021-3696: Fixed that a crafted PNG image could lead to out-of-bound write during huffman table handling (bsc#1191185)
• CVE-2021-3697: Fixed that a crafted JPEG image could lead to buffer underflow write in the heap (bsc#1191186)
• CVE-2022-28733: Fixed fragmentation math in net/ip (bsc#1198460)
• CVE-2022-28734: Fixed an out-of-bound write for split http headers (bsc#1198493)
• CVE-2022-28736: Fixed a use-after-free in chainloader command (bsc#1198496)
• Update SBAT security contact (bsc#1193282)
• Bump grub's SBAT generation to 2

This update for grub2 fixes the following issues:

Security fixes and hardenings for Boothole 3 / Boothole 2022 (bsc#1198581)

• CVE-2021-3695: Fixed that a crafted PNG grayscale image could lead to out-of-bounds write in heap (bsc#1191184)
• CVE-2021-3696: Fixed that a crafted PNG image could lead to out-of-bound write during huffman table handling (bsc#1191185)
• CVE-2021-3697: Fixed that a crafted JPEG image could lead to buffer underflow write in the heap (bsc#1191186)
• CVE-2022-28733: Fixed fragmentation math in net/ip (bsc#1198460)
• CVE-2022-28734: Fixed an out-of-bound write for split http headers (bsc#1198493)
• CVE-2022-28736: Fixed a use-after-free in chainloader command (bsc#1198496)
• Update SBAT security contact (bsc#1193282)
• Bump grub's SBAT generation to 2

This update for grub2 fixes the following issues:

Security fixes and hardenings for boothole 3 / boothole 2022 (bsc#1198581)

• CVE-2021-3695: Fixed that a crafted PNG grayscale image could lead to out-of-bounds write in heap (bsc#1191184)

• CVE-2021-3696: Fixed that a crafted PNG image could lead to out-of-bound write during huffman table handling (bsc#1191185)

• CVE-2021-3697: Fixed that a crafted JPEG image could lead to buffer underflow write in the heap (bsc#1191186)

• CVE-2022-28733: Fixed fragmentation math in net/ip (bsc#1198460)

• CVE-2022-28734: Fixed an out-of-bound write for split http headers (bsc#1198493)

• CVE-2022-28735: Fixed some verifier framework changes (bsc#1198495)

• CVE-2022-28736: Fixed a use-after-free in chainloader command (bsc#1198496)

• Update SBAT security contact (bsc#1193282)

• Bump grub's SBAT generation to 2

• Use boot disks in OpenFirmware, fixing regression caused when the root LV is completely in the boot LUN (bsc#1197948)

This update for grub2 fixes the following issues:

Security fixes and hardenings for boothole 3 / boothole 2022 (bsc#1198581)

• CVE-2021-3695: Fixed that a crafted PNG grayscale image could lead to out-of-bounds write in heap (bsc#1191184)
• CVE-2021-3696: Fixed that a crafted PNG image could lead to out-of-bound write during huffman table handling (bsc#1191185)
• CVE-2021-3697: Fixed that a crafted JPEG image could lead to buffer underflow write in the heap (bsc#1191186)
• CVE-2022-28733: Fixed fragmentation math in net/ip (bsc#1198460)
• CVE-2022-28734: Fixed an out-of-bound write for split http headers (bsc#1198493)
• CVE-2022-28735: Fixed some verifier framework changes (bsc#1198495)
• CVE-2022-28736: Fixed a use-after-free in chainloader command (bsc#1198496)
• Update SBAT security contact (bsc#1193282)
• Bump grub's SBAT generation to 2

Other bugs fixed:

• Use boot disks in OpenFirmware, fixing regression caused when the root LV is completely in the boot LUN (bsc#1197948)
• Fix grub-install error when efi system partition is created as mdadm software raid1 device (bsc#1179981) (bsc#1195204)
• Fix error in grub-install when linux root device is on lvm thin volume (bsc#1192622) (bsc#1191974)
• Fix wrong default entry when booting snapshot (bsc#1159205)
• Add support for simplefb (boo#1193532).
• Fix error lvmid disk cannot be found after second disk added to the root volume group (bsc#1189874) (bsc#1071559)
• Fix error /boot/grub2/locale/POSIX.gmo not found (bsc#1189769)
• Fix unknown TPM error on buggy uefi firmware (bsc#1191504)
• Fix arm64 kernel image not aligned on 64k boundary (bsc#1192522)

This update for grub2 fixes the following issues:

Security fixes and hardenings for boothole 3 / boothole 2022 (bsc#1198581)

• CVE-2021-3695: Fixed that a crafted PNG grayscale image could lead to out-of-bounds write in heap (bsc#1191184)

• CVE-2021-3696: Fixed that a crafted PNG image could lead to out-of-bound write during huffman table handling (bsc#1191185)

• CVE-2021-3697: Fixed that a crafted JPEG image could lead to buffer underflow write in the heap (bsc#1191186)

• CVE-2022-28733: Fixed fragmentation math in net/ip (bsc#1198460)

• CVE-2022-28734: Fixed an out-of-bound write for split http headers (bsc#1198493)

• CVE-2022-28735: Fixed some verifier framework changes (bsc#1198495)

• CVE-2022-28736: Fixed a use-after-free in chainloader command (bsc#1198496)

• Update SBAT security contact (bsc#1193282)

• Bump grub's SBAT generation to 2

• Use boot disks in OpenFirmware, fixing regression caused when the root LV is completely in the boot LUN (bsc#1197948)

Daniel Axtens discovered that specially crafted images could cause a heap-based out-of-bonds write. A local attacker could possibly use this to circumvent secure boot protections. (CVE-2021-3695)

Daniel Axtens discovered that specially crafted images could cause out-of-bonds read and write. A local attacker could possibly use this to circumvent secure boot protections. (CVE-2021-3696)

Daniel Axtens discovered that specially crafted images could cause buffer underwrite which allows arbitrary data to be written to a heap. A local attacker could possibly use this to circumvent secure boot protections. (CVE-2021-3697)

It was discovered that GRUB2 configuration files were created with the wrong permissions. An attacker could possibly use this to leak encrypted passwords. (CVE-2021-3981)

Daniel Axtens discovered that specially crafted IP packets could cause an integer underflow and write past the end of a buffer. An attacker could possibly use this to circumvent secure boot protections. (CVE-2022-28733)

Daniel Axtens discovered that specially crafted HTTP headers can cause an out-of-bounds write of a NULL byte. An attacker could possibly use this to corrupt GRUB2's internal data. (CVE-2022-28734)

Julian Andres Klode discovered that GRUB2 shim_lock allowed non- kernel files to be loaded. A local attack could possibly use this to circumvent secure boot protections. (CVE-2022-28735)

Chris Coulson discovered that executing chainloaders more than once caused a use-after-free vulnerability. A local attack could possibly use this to circumvent secure boot protections. (CVE-2022-28736)

Chris Coulson discovered that specially crafted executables could cause shim to make out-of-bound writes. A local attack could possibly use this to circumvent secure boot protections. (CVE-2022-28737)

Zhang Boyang discovered that specially crafted unicode sequences could lead to an out-of-bounds write to a heap. A local attacker could possibly use this to circumvent secure boot protections. (CVE-2022-3775)