CVE-2026-53008 in Linux
Summary
by MITRE • 06/24/2026
In the Linux kernel, the following vulnerability has been resolved:
ice: fix race condition in TX timestamp ring cleanup
Fix a race condition between ice_free_tx_tstamp_ring() and ice_tx_map() that can cause a NULL pointer dereference.
ice_free_tx_tstamp_ring currently clears the ICE_TX_FLAGS_TXTIME flag after NULLing the tstamp_ring. This could allow a concurrent ice_tx_map call on another CPU to dereference the tstamp_ring, which could lead to a NULL pointer dereference.
CPU A:ice_free_tx_tstamp_ring() | CPU B:ice_tx_map() --------------------------------|--------------------------------- tx_ring->tstamp_ring = NULL | | ice_is_txtime_cfg() -> true | tstamp_ring = tx_ring->tstamp_ring | tstamp_ring->count // NULL deref! flags &= ~ICE_TX_FLAGS_TXTIME |
Fix by: 1. Reordering ice_free_tx_tstamp_ring() to clear the flag before NULLing the pointer, with smp_wmb() to ensure proper ordering. 2. Adding smp_rmb() in ice_tx_map() after the flag check to order the flag read before the pointer read, using READ_ONCE() for the pointer, and adding a NULL check as a safety net. 3. Converting tx_ring->flags from u8 to DECLARE_BITMAP() and using atomic bitops (set_bit(), clear_bit(), test_bit()) for all flag operations throughout the driver: - ICE_TX_RING_FLAGS_XDP - ICE_TX_RING_FLAGS_VLAN_L2TAG1 - ICE_TX_RING_FLAGS_VLAN_L2TAG2 - ICE_TX_RING_FLAGS_TXTIME
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Analysis
by VulDB Data Team • 06/25/2026
The vulnerability identified in the linux kernel represents a critical race condition within the ice network driver that can lead to system instability through null pointer dereference. This issue occurs specifically during the cleanup of transmission timestamp rings where concurrent operations between different cpu cores create an unsafe execution path. The problem manifests when one cpu core executes ice_free_tx_tstamp_ring() while another core concurrently processes ice_tx_map() operations, creating a temporal window where memory access patterns can result in system crashes or undefined behavior.
The technical flaw stems from improper ordering of operations within the driver's synchronization mechanism. During the cleanup process, ice_free_tx_tstamp_ring() first nulls the tstamp_ring pointer before clearing the ICE_TX_FLAGS_TXTIME flag, which creates an opportunity for another cpu core to access the already-nullified ring structure. The race condition is particularly dangerous because the ice_tx_map() function performs a check using ice_is_txtime_cfg() that returns true, then proceeds to dereference tx_ring->tstamp_ring without proper synchronization guarantees. This sequence can cause a null pointer dereference when the tstamp_ring has been set to NULL by the cleanup routine but before the flag clearing operation completes.
The operational impact of this vulnerability extends beyond simple system crashes to potentially compromise network reliability and system stability in high-concurrency environments. When multiple threads or cpu cores are actively managing network transmission operations, the timing window for this race condition becomes more frequent, increasing the likelihood of system instability. Network applications relying on precise timestamping capabilities could experience data loss or complete service disruption. Additionally, the vulnerability affects systems where the ice driver manages high-throughput network traffic, making it particularly concerning for enterprise and data center environments.
The fix implemented addresses the root cause through multiple layers of synchronization improvements that align with established best practices in concurrent programming. The solution involves reordering operations within ice_free_tx_tstamp_ring() to clear the flag before nullifying the pointer while using smp_wmb() to ensure proper memory ordering between cores. The addition of smp_rmb() in ice_tx_map() ensures that flag reads occur before pointer reads, with READ_ONCE() providing safe access patterns for the pointer variable. The final enhancement converts the simple u8 flags field into a DECLARE_BITMAP structure with atomic bit operations, which provides better scalability and eliminates potential issues with flag manipulation across multiple cores. This approach follows principles from the common weakness enumeration framework where CWE-362 describes concurrent execution using shared data without proper synchronization, and aligns with attack techniques documented in the attack tree methodology under privilege escalation through system instability. The complete solution ensures that all flag operations maintain atomicity and proper ordering constraints necessary for safe multi-core operation within the driver's complex network processing pipeline.
The comprehensive mitigation strategy provides not only immediate protection against the identified race condition but also establishes a more robust foundation for future driver enhancements. By converting to atomic bit operations and implementing proper memory barriers, the driver now demonstrates adherence to modern kernel development practices that emphasize thread safety and concurrent access control. The fix ensures that timestamping functionality remains reliable even under high-concurrency workloads while maintaining backward compatibility with existing network applications. This resolution directly addresses security concerns related to denial of service attacks that could exploit such race conditions to destabilize systems running the affected ice driver components.