CVE-2023-53398 in Linux
Summary
by MITRE • 09/18/2025
In the Linux kernel, the following vulnerability has been resolved:
mlx5: fix possible ptp queue fifo use-after-free
Fifo indexes are not checked during pop operations and it leads to potential use-after-free when poping from empty queue. Such case was possible during re-sync action. WARN_ON_ONCE covers future cases.
There were out-of-order cqe spotted which lead to drain of the queue and use-after-free because of lack of fifo pointers check. Special check and counter are added to avoid resync operation if SKB could not exist in the fifo because of OOO cqe (skb_id must be between consumer and producer index).
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Analysis
by VulDB Data Team • 12/13/2025
The vulnerability CVE-2023-53398 affects the Linux kernel's mlx5 driver, specifically addressing a use-after-free condition in the Precision Time Protocol (PTP) queue fifo implementation. This issue resides within the Mellanox ConnectX network adapter driver family, which provides high-performance networking capabilities including hardware-assisted timestamping for time-sensitive applications. The flaw manifests when processing completion queue entries (CQE) in the PTP queue management system, where proper bounds checking is absent during fifo pop operations.
The technical root cause stems from insufficient validation of fifo index boundaries during pop operations, creating a scenario where the system attempts to access memory locations that have already been freed. This occurs particularly during re-synchronization actions when the driver processes out-of-order completion queue entries that disrupt normal fifo pointer management. The absence of proper index validation allows for situations where the consumer index can advance beyond the producer index, leading to memory access violations when attempting to pop from what appears to be an empty queue but still contains freed memory references. This vulnerability specifically impacts the mlx5 driver's handling of PTP timestamping operations that are critical for industrial automation, financial trading systems, and other time-sensitive network applications requiring precise timing measurements.
The operational impact of this vulnerability extends beyond simple memory corruption to potentially compromise system stability and availability. When triggered, the use-after-free condition can result in kernel panics, system crashes, or unpredictable behavior in network operations that depend on precise timing. The vulnerability is particularly concerning in production environments where network reliability is paramount, as it could lead to service disruption during critical synchronization operations. The presence of out-of-order CQE processing further complicates the scenario, as it indicates that the driver's handling of asynchronous network events creates race conditions that can be exploited to trigger the memory corruption. The WARN_ON_ONCE mechanism that was added serves as a diagnostic tool but does not prevent the underlying vulnerability, making it a latent issue that could manifest under specific network load conditions or during system maintenance operations.
Mitigation strategies for CVE-2023-53398 should prioritize applying the kernel patches released by the Linux kernel security team, which include the necessary fifo index validation checks and enhanced error handling for PTP queue operations. Organizations should implement comprehensive monitoring of system logs for WARN_ON_ONCE messages that may indicate the vulnerability's occurrence, particularly in environments where PTP functionality is actively used. Network administrators should also consider implementing additional redundancy measures for time-critical applications that depend on the affected mlx5 driver functionality. The fix addresses the core issue by adding proper bounds checking between consumer and producer fifo pointers, ensuring that skb_id values remain within valid ranges before queue operations are performed. This aligns with common security practices for preventing use-after-free vulnerabilities as outlined in CWE-416, which specifically addresses the use of freed memory. The vulnerability's characteristics also relate to ATT&CK technique T1499.004, which involves network disruption through manipulation of network device drivers, as the compromised driver functionality could be leveraged to create denial-of-service conditions in networked systems. Organizations should conduct thorough testing of patched systems to ensure that the driver modifications do not introduce performance regressions in normal network operations while maintaining the enhanced memory safety protections.