CVE-2026-72273 in Linux
Summary
by MITRE • 08/15/2026
In the Linux kernel, the following vulnerability has been resolved:
fbdev: efifb: fix memory leak in efifb_probe()
Since commit 73ce73c30ba9 ("fbdev: Transfer video= option strings to caller; clarify ownership") the string returned from fb_get_options() is expected to be freed by the caller, but the string is not freed in efifb_probe(). Fix that by freeing the option string after setup.
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Analysis
by VulDB Data Team • 08/15/2026
The vulnerability identified in the Linux kernel represents a memory leak within the efifb driver component that operates under the frame buffer device subsystem. This issue specifically affects the efifb_probe function which handles the initialization and setup of EFI framebuffer devices. The flaw emerged following a significant code change in commit 73ce73c30ba9 that altered how video option strings are managed within the fbdev framework. Prior to this modification, the fb_get_options() function handled memory management for option strings internally, but the subsequent change shifted this responsibility to the caller functions. The efifb driver failed to properly implement this new ownership model by not freeing the string returned from fb_get_options(), resulting in a persistent memory leak that accumulates with each driver probe operation.
The technical implementation of this vulnerability stems from improper resource management practices within kernel space code execution. When efifb_probe() invokes fb_get_options() to retrieve video parameter strings for configuration purposes, it receives a dynamically allocated string buffer that must now be explicitly freed by the calling function according to the updated API contract. The driver's failure to execute proper memory cleanup operations means that every successful probe operation leaves behind an unreleased memory segment that cannot be reclaimed by the system's memory management subsystem. This type of resource leak represents a classic category of vulnerability classified under CWE-401 as "Improper Release of Memory Before Removing Last Reference" and aligns with the broader ATT&CK technique T1490 for "Inhibit System Recovery" through resource exhaustion attacks.
The operational impact of this memory leak manifests primarily through gradual system resource degradation over time, particularly affecting systems running extensive graphical workloads or those with frequent driver initialization cycles. While individual leaks may appear trivial in magnitude, the cumulative effect across multiple probe operations can lead to significant memory consumption that impacts overall system performance and stability. The vulnerability is particularly concerning in embedded systems or virtualized environments where memory resources are constrained, as it could contribute to system instability or prevent proper operation of graphics subsystems. Attackers could potentially exploit this weakness to facilitate denial-of-service conditions by repeatedly triggering driver probe operations, causing progressive memory exhaustion that eventually impacts critical system functions.
Mitigation strategies for this vulnerability require immediate application of the kernel patch that implements proper string freeing in efifb_probe() function. System administrators should prioritize updating their Linux kernel installations to versions containing this fix, particularly those running EFI-based systems with active framebuffer operations. The solution involves adding a single free() call after the option string is processed and utilized during setup operations, ensuring that all dynamically allocated memory is properly returned to the system heap. Organizations maintaining critical infrastructure should conduct thorough testing of kernel updates to verify compatibility with existing graphics configurations and driver dependencies. Additionally, monitoring systems should be implemented to detect unusual memory consumption patterns that might indicate similar resource management issues in other kernel subsystems, as this vulnerability demonstrates the importance of proper memory lifecycle management in kernel space operations.