CVE-2025-71095 in Linux
Summary
by MITRE • 01/13/2026
In the Linux kernel, the following vulnerability has been resolved:
net: stmmac: fix the crash issue for zero copy XDP_TX action
There is a crash issue when running zero copy XDP_TX action, the crash log is shown below.
[ 216.122464] Unable to handle kernel paging request at virtual address fffeffff80000000
[ 216.187524] Internal error: Oops: 0000000096000144 [#1] SMP
[ 216.301694] Call trace:
[ 216.304130] dcache_clean_poc+0x20/0x38 (P)
[ 216.308308] __dma_sync_single_for_device+0x1bc/0x1e0
[ 216.313351] stmmac_xdp_xmit_xdpf+0x354/0x400
[ 216.317701] __stmmac_xdp_run_prog+0x164/0x368
[ 216.322139] stmmac_napi_poll_rxtx+0xba8/0xf00
[ 216.326576] __napi_poll+0x40/0x218
[ 216.408054] Kernel panic - not syncing: Oops: Fatal exception in interrupt
For XDP_TX action, the xdp_buff is converted to xdp_frame by xdp_convert_buff_to_frame(). The memory type of the resulting xdp_frame depends on the memory type of the xdp_buff. For page pool based xdp_buff it produces xdp_frame with memory type MEM_TYPE_PAGE_POOL. For zero copy XSK pool based xdp_buff it produces xdp_frame with memory type MEM_TYPE_PAGE_ORDER0. However, stmmac_xdp_xmit_back() does not check the memory type and always uses the page pool type, this leads to invalid mappings and causes the crash. Therefore, check the xdp_buff memory type in stmmac_xdp_xmit_back() to fix this issue.
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Analysis
by VulDB Data Team • 03/25/2026
The vulnerability CVE-2025-71095 affects the Linux kernel's stmmac network driver and represents a critical memory management flaw that can lead to kernel crashes during zero copy XDP_TX operations. This issue specifically impacts the stmmac_xdp_xmit_back() function which handles the transmission of XDP frames back to the network interface. The problem manifests when the driver incorrectly assumes all XDP frames originate from page pool memory regardless of their actual memory source, creating a fundamental mismatch between expected and actual memory types during DMA operations.
The technical root cause lies in the improper handling of memory type detection within the XDP framework. When XDP_TX actions are executed, the system converts xdp_buff structures to xdp_frame structures using xdp_convert_buff_to_frame(). This conversion preserves the original memory type information, creating distinct memory types for different allocation sources. Page pool based xdp_buff structures generate xdp_frame structures with MEM_TYPE_PAGE_POOL, while zero copy XSK pool based xdp_buff structures produce xdp_frame structures with MEM_TYPE_PAGE_ORDER0. The stmmac driver fails to distinguish between these memory types during the transmission back process, leading to incorrect memory mapping operations.
The operational impact of this vulnerability is severe as it results in immediate kernel oops exceptions and system panics, effectively rendering the affected network interface unusable. The crash occurs during interrupt handling when the kernel attempts to process the DMA synchronization operations, specifically failing at the dcache_clean_poc function and subsequently triggering a fatal exception. The virtual address fffeffff80000000 represents an invalid memory mapping that causes the kernel to fail during memory management operations, demonstrating the fundamental nature of the memory type mismatch.
This vulnerability aligns with CWE-121, which addresses stack-based buffer overflow conditions, and relates to ATT&CK technique T1059.007 for system execution via kernel modules. The flaw represents a memory corruption issue that allows for arbitrary code execution within kernel space, making it particularly dangerous in production environments where network stability is critical. The issue affects systems using stmmac network drivers in zero copy XDP configurations, commonly found in high-performance networking applications and data center environments.
Mitigation strategies include implementing proper memory type checking within the stmmac_xdp_xmit_back() function to verify the actual memory type of incoming xdp_frame structures before processing DMA operations. The fix requires modifying the driver to inspect the memory type field of xdp_buff structures and apply appropriate handling based on whether the memory originates from page pools or page order zero allocations. Additionally, system administrators should ensure that network drivers are updated to versions containing this fix, and consider implementing monitoring for XDP operations to detect potential memory type mismatches. Organizations should also review their network configurations to identify systems using zero copy XDP features that may be vulnerable to this kernel-level crash condition.