CVE-2024-26952 in Linux
Summary
by MITRE • 05/01/2024
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix potencial out-of-bounds when buffer offset is invalid
I found potencial out-of-bounds when buffer offset fields of a few requests is invalid. This patch set the minimum value of buffer offset field to ->Buffer offset to validate buffer length.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 01/26/2026
The vulnerability identified as CVE-2024-26952 affects the Linux kernel's ksmbd implementation, which provides SMB/CIFS file sharing capabilities. This issue represents a critical out-of-bounds memory access condition that could potentially allow remote attackers to execute arbitrary code or cause system instability. The ksmbd subsystem serves as a kernel-space implementation for SMB protocol handling, making it a crucial component for network file sharing operations in Linux environments. When processing certain SMB requests, the kernel fails to properly validate buffer offset fields, creating opportunities for memory corruption that could be exploited to gain unauthorized access to system resources.
The technical flaw manifests in the validation logic of buffer offset fields within specific SMB request processing pathways. The vulnerability occurs when invalid buffer offset values are encountered during request handling, allowing attackers to manipulate memory access patterns beyond intended boundaries. This particular weakness stems from insufficient input validation where the system does not properly enforce minimum bounds for buffer offset fields before proceeding with memory operations. The patch implemented addresses this by establishing a minimum threshold value for the buffer offset field, effectively validating buffer length parameters before any memory access operations occur. This validation mechanism prevents maliciously crafted requests from triggering out-of-bounds memory accesses that could lead to information disclosure, privilege escalation, or denial of service conditions.
The operational impact of this vulnerability extends across various Linux systems utilizing ksmbd for SMB file sharing services, particularly affecting enterprise environments where network file sharing is prevalent. Attackers could exploit this weakness remotely by sending specially crafted SMB requests that manipulate buffer offset fields to cause memory corruption. The vulnerability's severity is compounded by the fact that it operates at the kernel level, meaning successful exploitation could result in complete system compromise. Systems running older kernel versions without the patched ksmbd implementation remain vulnerable, with potential consequences including unauthorized data access, system crashes, and privilege escalation to root-level access. Organizations with active SMB services and network shares are particularly at risk, as the vulnerability can be exploited without requiring authentication for certain attack vectors.
Mitigation strategies should prioritize immediate kernel updates containing the patched ksmbd implementation, as this represents the most effective defense against the identified vulnerability. System administrators should conduct comprehensive inventory assessments to identify all systems running ksmbd services and apply security patches promptly. Network segmentation and access controls should be implemented to limit exposure of SMB services to trusted networks only, reducing the attack surface available to potential adversaries. Additional defensive measures include monitoring for anomalous SMB traffic patterns and implementing intrusion detection systems that can identify suspicious buffer offset manipulations. The vulnerability aligns with CWE-129, which describes improper validation of array index or buffer offset, and maps to ATT&CK technique T1059.007 for command and scripting interpreter usage, as exploitation may involve crafting malicious SMB requests to trigger the vulnerable code path. Regular security audits and vulnerability assessments should be conducted to ensure all kernel components remain updated against emerging threats in the SMB protocol ecosystem.