CVE-2024-26988 in Linux
Summary
by MITRE • 05/01/2024
In the Linux kernel, the following vulnerability has been resolved:
init/main.c: Fix potential static_command_line memory overflow
We allocate memory of size 'xlen + strlen(boot_command_line) + 1' for static_command_line, but the strings copied into static_command_line are extra_command_line and command_line, rather than extra_command_line and boot_command_line.
When strlen(command_line) > strlen(boot_command_line), static_command_line will overflow.
This patch just recovers strlen(command_line) which was miss-consolidated with strlen(boot_command_line) in the commit f5c7310ac73e ("init/main: add checks for the return value of memblock_alloc*()")
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Analysis
by VulDB Data Team • 02/06/2026
The vulnerability CVE-2024-26988 represents a critical memory overflow issue within the Linux kernel's initialization process, specifically in the init/main.c file. This flaw occurs during the allocation and population of the static_command_line buffer, which serves as a crucial component in kernel command line parameter handling. The vulnerability stems from a fundamental error in memory calculation and string copying logic that was introduced in a previous commit, creating a scenario where kernel memory can be overwritten beyond its allocated boundaries. The issue is particularly concerning as it affects the very foundation of kernel initialization, potentially allowing attackers to corrupt kernel memory structures and compromise system integrity.
The technical implementation of this vulnerability involves a miscalculation in the memory allocation formula where the kernel allocates memory of size 'xlen + strlen(boot_command_line) + 1' for the static_command_line buffer. However, the actual strings copied into this buffer are extra_command_line and command_line rather than the expected extra_command_line and boot_command_line. This discrepancy creates a scenario where if the command_line string exceeds the boot_command_line string in length, the static_command_line buffer becomes insufficiently sized, leading to memory overflow conditions. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, though in this case it manifests as a heap-based memory corruption due to the dynamic allocation nature of the affected buffer. The flaw was introduced in commit f5c7310ac73e which added checks for memblock_alloc*() return values but inadvertently swapped the string length calculations, creating a subtle but critical error in the memory management logic.
The operational impact of CVE-2024-26988 extends far beyond simple memory corruption, as it presents a significant attack surface that could be exploited through kernel memory corruption techniques. An attacker who can influence the command line parameters during kernel boot could potentially leverage this vulnerability to execute arbitrary code within kernel space, effectively bypassing kernel protection mechanisms such as kernel address space layout randomization and stack canaries. This type of vulnerability aligns with ATT&CK technique T1068 which describes "Exploitation for Privilege Escalation" and represents a critical pathway for attackers to gain elevated privileges. The vulnerability affects all Linux systems that utilize the affected kernel version, making it particularly dangerous in environments where kernel boot parameters can be manipulated by untrusted users or processes. The memory corruption could lead to system crashes, data corruption, or more sinisterly, provide a foothold for persistent kernel-level malware that could maintain system control across reboots.
Mitigation strategies for CVE-2024-26988 require immediate patch application from kernel vendors, as this vulnerability represents a critical security flaw that should not be delayed. System administrators should prioritize updating their kernel versions to include the fix that corrects the string length calculation and ensures proper memory allocation for the static_command_line buffer. Additionally, implementing kernel lockdown mechanisms and restricting boot parameter modifications can provide additional defensive layers. The fix involves recovering the correct strlen(command_line) calculation that was incorrectly consolidated with strlen(boot_command_line) during the problematic commit, ensuring that the memory allocation accounts for the actual string lengths that will be copied into the buffer. Organizations should also consider implementing kernel module signing and secure boot configurations to prevent unauthorized kernel modifications that could exploit this vulnerability. The vulnerability highlights the importance of thorough code review processes, particularly for critical kernel initialization code, and demonstrates the potential consequences of seemingly minor logic errors in system-level programming.