CVE-2023-53654 in Linux
Summary
by MITRE • 10/07/2025
In the Linux kernel, the following vulnerability has been resolved:
octeontx2-af: Add validation before accessing cgx and lmac
with the addition of new MAC blocks like CN10K RPM and CN10KB RPM_USX, LMACs are noncontiguous and CGX blocks are also noncontiguous. But during RVU driver initialization, the driver is assuming they are contiguous and trying to access cgx or lmac with their id which is resulting in kernel panic.
This patch fixes the issue by adding proper checks.
[ 23.219150] pc : cgx_lmac_read+0x38/0x70
[ 23.219154] lr : rvu_program_channels+0x3f0/0x498
[ 23.223852] sp : ffff000100d6fc80
[ 23.227158] x29: ffff000100d6fc80 x28: ffff00010009f880 x27:
000000000000005a [ 23.234288] x26: ffff000102586768 x25: 0000000000002500 x24:
fffffffffff0f000
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Analysis
by VulDB Data Team • 03/01/2026
The vulnerability CVE-2023-53654 affects the Linux kernel's octeontx2-af driver implementation, specifically within the RVU (Rapid Virtualization Unit) subsystem that manages networking hardware for Cavium OcteonTX2 platforms. This issue manifests as a kernel panic during driver initialization when the system attempts to access CGX (Common Graphics eXtension) and LMAC (Layer MAC) hardware blocks that are not properly validated for existence. The root cause stems from the driver's assumption that these hardware blocks are contiguous in memory and address space, a fundamental error that becomes critical when supporting newer hardware variants such as CN10K RPM and CN10KB RPM_USX which introduce noncontiguous memory layouts for their MAC blocks.
The technical flaw represents a classic buffer over-read or invalid memory access condition that aligns with CWE-125: "Out-of-bounds Read" and potentially CWE-787: "Out-of-bounds Write" when considering the kernel panic behavior. During RVU driver initialization, the code attempts to access CGX and LMAC hardware registers using their identifier indices without first validating whether these hardware blocks actually exist at the specified locations. The stack trace reveals the execution path leading to the crash, with the cgx_lmac_read function being called from rvu_program_channels, indicating that the driver assumes contiguous hardware block mapping regardless of the actual physical hardware configuration. This particular vulnerability demonstrates a failure in memory management and hardware abstraction layer validation.
The operational impact of this vulnerability is severe as it can cause complete system crashes and kernel panics during boot sequences or driver initialization phases, effectively rendering affected systems unusable until the kernel is rebooted and the driver properly loads. This represents a critical availability issue that could be exploited in denial-of-service scenarios, particularly in environments where automated system restarts or continuous operation is required. The vulnerability affects systems utilizing Cavium OcteonTX2 networking hardware, including servers and network appliances that rely on the RVU driver for network interface management. The issue becomes particularly problematic in high-availability deployments where unexpected kernel panics could result in service interruptions and potential data loss.
Mitigation strategies should focus on implementing proper hardware block validation checks before attempting any memory accesses or register operations. The fix implemented in the patch adds necessary validation routines that verify the existence and proper mapping of CGX and LMAC hardware blocks before any access operations occur. System administrators should ensure all affected kernels are updated with the patched version that includes the validation logic. Additionally, monitoring systems should be configured to detect kernel panic events and automatically trigger alerts for investigation. The vulnerability also highlights the importance of proper hardware abstraction layer design in kernel drivers, emphasizing that assumptions about hardware contiguity should never be made without explicit validation, a principle that aligns with ATT&CK technique T1499.001: "File and Directory Permissions Modification" and T1070.006: "Indicator Removal on Host" through proper error handling rather than allowing crashes. Organizations should also implement comprehensive testing procedures for new hardware variants to identify similar mapping assumptions before deployment in production environments.