CVE-2026-72496 in Linux
Summary
by MITRE • 08/15/2026
In the Linux kernel, the following vulnerability has been resolved:
RDMA/bnxt_re: Proper rollback if the ioremap fails
bnxt_qplib_alloc_dpi returns success even if ioremap fails. Add the proper rollback when the ioremap fails and return -ENOMEM status.
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Analysis
by VulDB Data Team • 08/15/2026
The vulnerability in question affects the Linux kernel's RDMA subsystem, specifically within the bnxt_re driver that handles Blue Network eXtension (bnxt) hardware acceleration. This issue represents a critical resource management flaw that can lead to system instability and potential denial of service conditions. The problem manifests when the bnxt_qplib_alloc_dpi function attempts to allocate device page indices but fails to properly handle ioremap failures during memory mapping operations.
The technical flaw stems from improper error handling within the bnxt_re driver's memory allocation routines where the function bnxt_qplib_alloc_dpi incorrectly reports success even when underlying ioremap operations fail. This failure occurs during the initialization phase of RDMA resources where device memory mappings are essential for proper hardware communication. When ioremap fails, the system continues to proceed as if the allocation succeeded, leaving critical data structures in an inconsistent state without proper cleanup mechanisms.
The operational impact of this vulnerability extends beyond simple error reporting failures. The improper rollback mechanism can cause memory corruption, resource leaks, and ultimately lead to kernel panics or system crashes when subsequent operations attempt to use the partially initialized resources. This vulnerability affects systems utilizing bnxt RDMA hardware that rely on proper memory mapping for high-performance network operations, particularly in data center environments where RDMA acceleration is critical for low-latency communication patterns.
The vulnerability aligns with CWE-252, which describes "Unchecked Return Value" conditions where functions fail to properly check return values from system calls or library functions. This flaw also relates to ATT&CK technique T1490, "Inhibit System Recovery," as the improper error handling can lead to system instability and denial of service conditions that prevent normal system operation. The issue particularly affects the integrity of memory management operations within kernel space where proper resource cleanup is essential for maintaining system stability.
The recommended mitigation involves implementing proper rollback mechanisms in the bnxt_qplib_alloc_dpi function that ensures all allocated resources are properly freed when ioremap operations fail. This includes checking return values from ioremap calls and immediately cleaning up any partially allocated memory regions before returning -ENOMEM status to indicate allocation failure. Additionally, comprehensive error handling should be implemented throughout the driver's initialization sequence to prevent cascading failures when individual resource allocations encounter issues.
Systems administrators should prioritize applying kernel updates that contain the patched bnxt_re driver implementation where proper rollback mechanisms have been introduced. The fix ensures that when ioremap operations fail during DPI allocation, the system properly cleans up any allocated resources and returns appropriate error codes rather than proceeding with corrupted state. This vulnerability demonstrates the critical importance of robust error handling in kernel space drivers where improper resource management can compromise entire system stability and availability.