Gnu Grub2 vulnerabilities
54 vulnerabilities
Known vulnerabilities in Gnu Grub2, newest first, with CVSS severity, EPSS, KEV listings, ransomware use and the affected versions.
CVE-2021-20233alpinegrub+11
EPSS score0.60%
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.CVE-2021-20225alpinegrub+11EPSS score1.01%
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.CVE-2021-46705gnugrub2+3EPSS score0.24%
A Insecure Temporary File vulnerability in grub-once of grub2 in SUSE Linux Enterprise Server 15 SP4, openSUSE Factory allows local attackers to truncate arbitrary files. This issue affects: SUSE Linux Enterprise Server 15 SP4 grub2 versions prior to 2.06-150400.7.1. SUSE openSUSE Factory grub2 versions prior to 2.06-18.1.CVE-2021-3695debiangrub2+16EPSS score0.46%
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.CVE-2021-3981debiangrub2+30EPSS score0.32%
A flaw in grub2 was found where its configuration file, known as grub.cfg, is being created with the wrong permission set allowing non privileged users to read its content. This represents a low severity confidentiality issue, as those users can eventually read any encrypted passwords present in grub.cfg. This flaw affects grub2 2.06 and previous versions. This issue has been fixed in grub upstream but no version with the fix is currently released.CVE-2021-3418alpinegrub+1EPSS score0.47%
If certificates that signed grub are installed into db, grub can be booted directly. It will then boot any kernel without signature validation. The booted kernel will think it was booted in secureboot mode and will implement lockdown, yet it could have been tampered. This flaw is a reintroduction of CVE-2020-15705 and only affects grub2 versions prior to 2.06 and upstream and distributions using the shim_lock mechanism.CVE-2021-3696debiangrub2+15EPSS score0.47%
A heap out-of-bounds write may heppen during the handling of Huffman tables in the PNG reader. This may lead to data corruption in the heap space. Confidentiality, Integrity and Availablity impact may be considered Low as it's very complex to an attacker control the encoding and positioning of corrupted Huffman entries to achieve results such as arbitrary code execution and/or secure boot circumvention. This flaw affects grub2 versions prior grub-2.12.CVE-2021-3697alpinegrub+15EPSS score0.46%
A crafted JPEG image may lead the JPEG reader to underflow its data pointer, allowing user-controlled data to be written in heap. To a successful to be performed the attacker needs to perform some triage over the heap layout and craft an image with a malicious format and payload. This vulnerability can lead to data corruption and eventual code execution or secure boot circumvention. This flaw affects grub2 versions prior grub-2.12.CVE-2015-8370debiangrub2+23EPSS score1.09%
Multiple integer underflows in Grub2 1.98 through 2.02 allow physically proximate attackers to bypass authentication, obtain sensitive information, or cause a denial of service (disk corruption) via backspace characters in the (1) grub_username_get function in grub-core/normal/auth.c or the (2) grub_password_get function in lib/crypto.c, which trigger an "Off-by-two" or "Out of bounds overwrite" memory error.CVE-2025-54770debiangrub2+4EPSS score0.15%
A vulnerability has been identified in the GRUB2 bootloader's network module that poses an immediate Denial of Service (DoS) risk. This flaw is a Use-after-Free issue, caused because the net_set_vlan command is not properly unregistered when the network module is unloaded from memory. An attacker who can execute this command can force the system to access memory locations that are no longer valid. Successful exploitation leads directly to system instability, which can result in a complete crash and halt system availabilityCVE-2025-54771debiangrub2+4EPSS score0.14%
A use-after-free vulnerability has been identified in the GNU GRUB (Grand Unified Bootloader). The flaw occurs because the file-closing process incorrectly retains a memory pointer, leaving an invalid reference to a file system structure. An attacker could exploit this vulnerability to cause grub to crash, leading to a Denial of Service. Possible data integrity or confidentiality compromise is not discarded.CVE-2025-61663debiangrub2+4EPSS score0.13%
A vulnerability has been identified in the GRUB2 bootloader's normal command that poses an immediate Denial of Service (DoS) risk. This flaw is a Use-after-Free issue, caused because the normal command is not properly unregistered when the module is unloaded. An attacker who can execute this command can force the system to access memory locations that are no longer valid. Successful exploitation leads directly to system instability, which can result in a complete crash and halt system availability. Impact on the data integrity and confidentiality is also not discarded.CVE-2025-61661debiangrub2+4EPSS score0.19%
A vulnerability has been identified in the GRUB (Grand Unified Bootloader) component. This flaw occurs because the bootloader mishandles string conversion when reading information from a USB device, allowing an attacker to exploit inconsistent length values. A local attacker can connect a maliciously configured USB device during the boot sequence to trigger this issue. A successful exploitation may lead GRUB to crash, leading to a Denial of Service. Data corruption may be also possible, although given the complexity of the exploit the impact is most likely limited.CVE-2025-61662debiangrub2+33EPSS score0.20%
A Use-After-Free vulnerability has been discovered in GRUB's gettext module. This flaw stems from a programming error where the gettext command remains registered in memory after its module is unloaded. An attacker can exploit this condition by invoking the orphaned command, causing the application to access a memory location that is no longer valid. An attacker could exploit this vulnerability to cause grub to crash, leading to a Denial of Service. Possible data integrity or confidentiality compromise is not discarded.CVE-2025-61664debiangrub2+4EPSS score0.14%
A vulnerability in the GRUB2 bootloader has been identified in the normal module. This flaw, a memory Use After Free issue, occurs because the normal_exit command is not properly unregistered when its related module is unloaded. An attacker can exploit this condition by invoking the command after the module has been removed, causing the system to improperly access a previously freed memory location. This leads to a system crash or possible impacts in data confidentiality and integrity.CVE-2025-1125debiangrub2+4EPSS score0.44%
When reading data from a hfs filesystem, grub's hfs filesystem module uses user-controlled parameters from the filesystem metadata to calculate the internal buffers size, however it misses to properly check for integer overflows. A maliciouly crafted filesystem may lead some of those buffer size calculation to overflow, causing it to perform a grub_malloc() operation with a smaller size than expected. As a result the hfsplus_open_compressed_real() function will write past of the internal buffer length. This flaw may be leveraged to corrupt grub's internal critical data and may result in arbitrary code execution by-passing secure boot protections.CVE-2025-0686debiangrub2+4EPSS score0.28%
A flaw was found in grub2. When performing a symlink lookup from a romfs filesystem, grub's romfs filesystem module uses user-controlled parameters from the filesystem geometry to determine the internal buffer size, however, it improperly checks for integer overflows. A maliciously crafted filesystem may lead some of those buffer size calculations to overflow, causing it to perform a grub_malloc() operation with a smaller size than expected. As a result, the grub_romfs_read_symlink() may cause out-of-bounds writes when the calling grub_disk_read() function. This issue may be leveraged to corrupt grub's internal critical data and can result in arbitrary code execution by-passing secure boot protections.CVE-2025-0685debiangrub2+4EPSS score0.28%
A flaw was found in grub2. When reading data from a jfs filesystem, grub's jfs filesystem module uses user-controlled parameters from the filesystem geometry to determine the internal buffer size, however, it improperly checks for integer overflows. A maliciouly crafted filesystem may lead some of those buffer size calculations to overflow, causing it to perform a grub_malloc() operation with a smaller size than expected. As a result, the grub_jfs_lookup_symlink() function will write past the internal buffer length during grub_jfs_read_file(). This issue can be leveraged to corrupt grub's internal critical data and may result in arbitrary code execution, by-passing secure boot protections.CVE-2025-0684debiangrub2+4EPSS score0.28%
A flaw was found in grub2. When performing a symlink lookup from a reiserfs filesystem, grub's reiserfs fs module uses user-controlled parameters from the filesystem geometry to determine the internal buffer size, however, it improperly checks for integer overflows. A maliciouly crafted filesystem may lead some of those buffer size calculations to overflow, causing it to perform a grub_malloc() operation with a smaller size than expected. As a result, the grub_reiserfs_read_symlink() will call grub_reiserfs_read_real() with a overflown length parameter, leading to a heap based out-of-bounds write during data reading. This flaw may be leveraged to corrupt grub's internal critical data and can result in arbitrary code execution, by-passing secure boot protections.CVE-2025-0689debiangrub2+4EPSS score0.48%
When reading data from disk, the grub's UDF filesystem module utilizes the user controlled data length metadata to allocate its internal buffers. In certain scenarios, while iterating through disk sectors, it assumes the read size from the disk is always smaller than the allocated buffer size which is not guaranteed. A crafted filesystem image may lead to a heap-based buffer overflow resulting in critical data to be corrupted, resulting in the risk of arbitrary code execution by-passing secure boot protections.