CVE-2024-36957 in Linux
Summary
by MITRE • 05/30/2024
In the Linux kernel, the following vulnerability has been resolved:
octeontx2-af: avoid off-by-one read from userspace
We try to access count + 1 byte from userspace with memdup_user(buffer, count + 1). However, the userspace only provides buffer of count bytes and only these count bytes are verified to be okay to access. To ensure the copied buffer is NUL terminated, we use memdup_user_nul instead.
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Analysis
by VulDB Data Team • 12/24/2025
The vulnerability identified as CVE-2024-36957 resides within the Linux kernel's octeontx2-af driver, representing a critical memory access flaw that could potentially enable privilege escalation or system instability. This issue specifically affects the handling of user-space buffer operations within the network acceleration driver for Cavium Octeon TX2 platforms. The flaw manifests when the kernel attempts to process data received from user-space applications, creating a dangerous scenario where memory boundaries are improperly validated. The vulnerability is classified as an off-by-one error that occurs during buffer copying operations, where the kernel incorrectly assumes additional memory space exists beyond what is actually provided by user-space applications.
The technical implementation of this vulnerability stems from the improper use of memory duplication functions within the kernel's driver code. When processing user-provided data, the kernel code employs memdup_user(buffer, count + 1) which attempts to copy count + 1 bytes from user-space memory. However, the actual user-space buffer only contains count bytes of valid data, creating a mismatch between expected and actual memory boundaries. This discrepancy occurs because the kernel's validation mechanism only verifies access to the first count bytes, leaving the additional byte vulnerable to potential read operations beyond the intended buffer limits. This type of vulnerability directly relates to CWE-129 and CWE-787, which address improper bounds checking and out-of-bounds read conditions respectively.
The operational impact of this vulnerability extends beyond simple memory corruption, potentially allowing malicious user-space processes to exploit the buffer overflow condition for privilege escalation attacks. Attackers could leverage this flaw to read kernel memory contents, potentially extracting sensitive information or manipulating kernel data structures. The vulnerability is particularly concerning in environments where untrusted user-space applications interact with kernel drivers, as it creates a pathway for attackers to bypass kernel security mechanisms. According to ATT&CK framework category T1068, this vulnerability could be exploited for local privilege escalation, while T1590 represents the reconnaissance phase where attackers might discover such kernel-level weaknesses. The octeontx2-af driver's role in network acceleration makes this particularly dangerous in high-performance computing environments where kernel-level access is critical.
The resolution for CVE-2024-36957 involves implementing proper memory handling through the use of memdup_user_nul instead of the problematic memdup_user function. This change ensures that the kernel properly handles null-termination requirements while maintaining appropriate bounds checking for user-space memory access. The fix addresses the fundamental issue by ensuring that only the actual user-provided buffer size is accessed, eliminating the off-by-one read condition that previously existed. This mitigation aligns with security best practices outlined in the Linux kernel security documentation and represents a standard approach for preventing buffer over-read vulnerabilities in kernel space. The solution demonstrates proper defensive programming principles where memory operations are validated against actual user-provided data boundaries rather than making assumptions about additional memory availability. System administrators should prioritize applying this kernel update across all affected systems, particularly those running network acceleration workloads that utilize the octeontx2-af driver, as the vulnerability presents a significant risk to system integrity and security posture.