CVE-2026-72038 in Linux
Summary
by MITRE • 08/15/2026
In the Linux kernel, the following vulnerability has been resolved:
net: liquidio: fix BAR resource leak on PF number failure
If cn23xx_get_pf_num() fails, the function returns without unmapping either BAR. Unmap both BARs before returning from the error path.
Found by manual code review.
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Analysis
by VulDB Data Team • 08/15/2026
The vulnerability identified in the Linux kernel pertains to a resource management flaw within the net liquidio driver, specifically affecting the cn23xx device family. This issue manifests as a memory leak scenario where the driver fails to properly release hardware resources when encountering an error condition during the initialization process. The problem occurs in the function cn23xx_get_pf_num() which is responsible for determining the physical function number of the network interface card, a critical step in establishing proper device communication channels.
The technical flaw stems from improper error handling within the driver's resource allocation logic. When the cn23xx_get_pf_num() function encounters a failure condition and returns early from the execution path, it neglects to unmap the Base Address Registers (BARs) that were previously mapped during the initialization sequence. BARs represent memory-mapped regions that provide access to hardware registers and other critical device resources, making their proper management essential for system stability. This resource leak represents a classic case of insufficient cleanup in error handling paths, where allocated hardware resources remain mapped and inaccessible to other processes or drivers.
The operational impact of this vulnerability extends beyond simple memory consumption issues, as it can lead to system instability and resource exhaustion over time. When multiple network interface cards are initialized or when the driver experiences repeated failure conditions, the accumulation of unmapped BAR resources can result in reduced system performance and potential device malfunction. The vulnerability becomes particularly concerning in high-throughput networking environments where the liquidio driver is frequently invoked during system boot processes or dynamic device reconfiguration scenarios. This resource leak could potentially be exploited by malicious actors to cause denial-of-service conditions through systematic resource exhaustion.
The fix implemented addresses this issue by ensuring that both BARs are properly unmapped before any error return occurs from the cn23xx_get_pf_num() function. This remediation follows established best practices for error handling in kernel drivers and aligns with the principles outlined in the Common Weakness Enumeration standard CWE-459, which specifically addresses inadequate cleanup of resources after errors. The solution demonstrates adherence to the ATT&CK framework's concept of privilege escalation through resource exhaustion attacks, where improper resource management can create opportunities for adversaries to consume system resources and degrade overall system functionality. This vulnerability highlights the critical importance of robust error handling in kernel space code, particularly when dealing with hardware resource allocation where failure to properly release resources can result in cascading system issues and reduced reliability across network infrastructure components.