CVE-2026-74286 in Linux
Summary
by MITRE • 08/15/2026
In the Linux kernel, the following vulnerability has been resolved:
net: pfcp: allocate per-cpu tstats for PFCP netdevs
PFCP uses dev_get_tstats64() as its ndo_get_stats64 callback, but pfcp_link_setup() does not request NETDEV_PCPU_STAT_TSTATS. The net core therefore leaves dev->tstats NULL for PFCP devices.
Creating a PFCP rtnetlink device can immediately ask the new netdev for stats while building the RTM_NEWLINK notification. That reaches dev_get_tstats64() and dereferences the NULL dev->tstats pointer.
Set pcpu_stat_type to NETDEV_PCPU_STAT_TSTATS during PFCP link setup so the net core allocates the storage expected by dev_get_tstats64().
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Analysis
by VulDB Data Team • 08/15/2026
This vulnerability exists within the Linux kernel's packet forwarding control plane implementation where the PFCP (Packet Forwarding Control Protocol) subsystem fails to properly initialize per-cpu statistics structures required for network device operations. The flaw occurs during the setup of PFCP rtnetlink devices when the pfcp_link_setup() function does not request the NETDEV_PCPU_STAT_TSTATS flag from the networking core, resulting in a null pointer assignment for the device's tstats field.
The technical implementation issue stems from the improper initialization of network device statistics structures within the PFCP subsystem. When PFCP devices are created through rtnetlink operations, the system attempts to retrieve statistics using dev_get_tstats64() as the ndo_get_stats64 callback function, but because the necessary per-cpu statistics allocation was never requested during device setup, the dev->tstats pointer remains uninitialized and NULL. This creates an immediate dereference of a null pointer when the RTM_NEWLINK notification is being constructed, leading to potential system crashes or undefined behavior.
The operational impact of this vulnerability extends beyond simple denial of service scenarios as it represents a fundamental flaw in how PFCP network devices interact with the kernel's networking subsystem. The vulnerability can be exploited through legitimate PFCP device creation operations, making it particularly concerning for network infrastructure components that rely on PFCP protocol support such as 5G core networks and mobile edge computing environments. This issue directly affects the stability and reliability of systems implementing PFCP functionality, potentially causing cascading failures in network control planes.
The mitigation strategy involves modifying the pfcp_link_setup() function to properly request per-cpu statistics allocation by setting the pcpu_stat_type field to NETDEV_PCPU_STAT_TSTATS during device initialization. This ensures that the networking core allocates the appropriate storage structures that dev_get_tstats64() expects, preventing the null pointer dereference that occurs during stats retrieval operations. From a cybersecurity perspective, this vulnerability aligns with CWE-476 which addresses NULL pointer dereferences and demonstrates how improper resource initialization can lead to critical system instability.
This vulnerability also relates to ATT&CK technique T1490 which involves data destruction through manipulation of system resources, as the null pointer dereference could potentially be leveraged to disrupt network operations or cause system crashes in environments relying on PFCP protocol implementations. The fix requires careful attention to ensure that all PFCP device creation paths properly initialize their statistics structures while maintaining compatibility with existing PFCP protocol behavior and network functionality requirements.
The root cause analysis reveals a design gap in the kernel's network device initialization framework where certain subsystems fail to properly declare their resource requirements during device setup. This type of vulnerability is particularly challenging to detect through automated testing as it requires specific conditions involving the interaction between device creation operations and statistics retrieval mechanisms, making it more susceptible to exploitation in production environments where PFCP functionality is actively used for network control plane operations.
This particular vulnerability demonstrates the complexity involved in maintaining proper resource management within kernel subsystems, where seemingly minor omissions in initialization procedures can lead to critical stability issues. The solution represents a straightforward fix that ensures proper resource allocation but highlights broader concerns about the robustness of kernel device initialization procedures and the importance of comprehensive testing for edge cases involving statistics retrieval operations in network subsystems.