CVE-2024-26811 in Linux
Summary
by MITRE • 04/08/2024
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: validate payload size in ipc response
If installing malicious ksmbd-tools, ksmbd.mountd can return invalid ipc response to ksmbd kernel server. ksmbd should validate payload size of ipc response from ksmbd.mountd to avoid memory overrun or slab-out-of-bounds. This patch validate 3 ipc response that has payload.
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Analysis
by VulDB Data Team • 08/05/2026
The vulnerability identified as CVE-2024-26811 affects the Linux kernel's ksmbd implementation, specifically addressing a critical security flaw in the inter-process communication mechanism between user-space tools and the kernel server. This issue resides within the ksmbd subsystem which provides SMB/CIFS file sharing capabilities in Linux environments. The vulnerability stems from insufficient validation of payload sizes in inter-process communication responses, creating a potential pathway for malicious actors to exploit memory corruption vulnerabilities through carefully crafted IPC messages.
The technical flaw manifests when maliciously installed ksmbd-tools components interact with ksmbd.mountd daemon, which can generate invalid IPC responses that are subsequently processed by the ksmbd kernel server. This particular vulnerability represents a classic buffer overflow scenario where the kernel server fails to validate the size of incoming payload data from the mountd daemon before processing it. The absence of proper bounds checking allows for memory overrun conditions that could lead to slab-out-of-bounds errors, where the kernel's memory management system attempts to access memory regions outside of allocated buffers. This type of vulnerability falls under CWE-129, which specifically addresses insufficient validation of length of input data, and more broadly under CWE-787, concerning out-of-bounds write operations.
The operational impact of this vulnerability extends beyond simple memory corruption, as it provides potential attackers with opportunities to execute arbitrary code within the kernel context, potentially leading to complete system compromise. Attackers could leverage this vulnerability by installing malicious ksmbd-tools packages that manipulate the IPC response payloads to trigger memory corruption conditions. The kernel server's failure to validate payload sizes creates a scenario where legitimate system operations could be disrupted, while simultaneously providing a potential attack vector for privilege escalation. This vulnerability directly maps to ATT&CK technique T1059.001 for command and scripting interpreter, as attackers could potentially use the compromised kernel components to execute malicious commands, and T1068 for exploit for privilege escalation through kernel-level memory corruption.
The patch addressing this vulnerability implements mandatory payload size validation for three specific IPC responses that contain payload data, ensuring that all incoming IPC messages from ksmbd.mountd are properly validated before being processed by the kernel server. This validation mechanism prevents memory overrun conditions and slab-out-of-bounds errors by enforcing strict size limits on all payload data. The fix aligns with security best practices outlined in the Linux kernel security documentation, specifically addressing the need for robust input validation in kernel-space components that handle inter-process communication. Organizations should prioritize applying this patch to prevent potential exploitation, particularly in environments where ksmbd services are actively deployed and where the risk of malicious package installation cannot be ruled out. The mitigation strategy should also include monitoring for unauthorized ksmbd-tools installations and implementing proper access controls to prevent malicious package deployment in production environments.