CVE-2025-68301 in Linux
Summary
by MITRE • 12/16/2025
In the Linux kernel, the following vulnerability has been resolved:
net: atlantic: fix fragment overflow handling in RX path
The atlantic driver can receive packets with more than MAX_SKB_FRAGS (17) fragments when handling large multi-descriptor packets. This causes an out-of-bounds write in skb_add_rx_frag_netmem() leading to kernel panic.
The issue occurs because the driver doesn't check the total number of fragments before calling skb_add_rx_frag(). When a packet requires more than MAX_SKB_FRAGS fragments, the fragment index exceeds the array bounds.
Fix by assuming there will be an extra frag if buff->len > AQ_CFG_RX_HDR_SIZE, then all fragments are accounted for. And reusing the existing check to prevent the overflow earlier in the code path.
This crash occurred in production with an Aquantia AQC113 10G NIC.
Stack trace from production environment: ``` RIP: 0010:skb_add_rx_frag_netmem+0x29/0xd0 Code: 90 f3 0f 1e fa 0f 1f 44 00 00 48 89 f8 41 89 ca 48 89 d7 48 63 ce 8b 90 c0 00 00 00 48 c1 e1 04 48 01 ca 48 03 90 c8 00 00 00 <48> 89 7a 30 44 89 52 3c 44 89 42 38 40 f6 c7 01 75 74 48 89 fa 83 RSP: 0018:ffffa9bec02a8d50 EFLAGS: 00010287 RAX: ffff925b22e80a00 RBX: ffff925ad38d2700 RCX: fffffffe0a0c8000 RDX: ffff9258ea95bac0 RSI: ffff925ae0a0c800 RDI: 0000000000037a40 RBP: 0000000000000024 R08: 0000000000000000 R09: 0000000000000021 R10: 0000000000000848 R11: 0000000000000000 R12: ffffa9bec02a8e24 R13: ffff925ad8615570 R14: 0000000000000000 R15: ffff925b22e80a00 FS: 0000000000000000(0000) GS:ffff925e47880000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff9258ea95baf0 CR3: 0000000166022004 CR4: 0000000000f72ef0 PKRU: 55555554 Call Trace: <IRQ> aq_ring_rx_clean+0x175/0xe60 [atlantic]
? aq_ring_rx_clean+0x14d/0xe60 [atlantic]
? aq_ring_tx_clean+0xdf/0x190 [atlantic]
? kmem_cache_free+0x348/0x450 ? aq_vec_poll+0x81/0x1d0 [atlantic]
? __napi_poll+0x28/0x1c0 ? net_rx_action+0x337/0x420 ```
Changes in v4: - Add Fixes: tag to satisfy patch validation requirements.
Changes in v3: - Fix by assuming there will be an extra frag if buff->len > AQ_CFG_RX_HDR_SIZE, then all fragments are accounted for.
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Analysis
by VulDB Data Team • 05/24/2026
The vulnerability described in CVE-2025-68301 affects the Linux kernel's atlantic network driver, specifically within the receive (RX) path handling of large multi-descriptor packets. This flaw manifests as an out-of-bounds write condition that can lead to a kernel panic, compromising system stability and availability. The issue is rooted in improper validation of packet fragment counts when processing incoming network data, particularly impacting the Aquantia AQC113 10G NIC hardware. The driver's failure to enforce a limit on the number of fragments per packet causes an overflow in the skb_add_rx_frag_netmem() function, which is responsible for adding received fragments to the socket buffer. This function operates on an array with a fixed size of MAX_SKB_FRAGS (17), and when packets exceed this limit, memory corruption occurs at the boundary of the allocated fragment array.
The technical root cause involves a missing bounds check in the packet processing logic of the atlantic driver. When handling packets that require more than 17 fragments, the driver does not validate whether the total fragment count would exceed the maximum allowed value. The problematic code path begins in the aq_ring_rx_clean function where received packets are processed through multiple descriptors, and continues through the skb_add_rx_frag() call which directly interacts with the kernel's memory management subsystem. This vulnerability is categorized as a buffer overflow condition that can result in memory corruption and system crashes, with the stack trace indicating that the fault occurs during the execution of skb_add_rx_frag_netmem at offset 0x29. The specific memory access pattern suggests that the driver attempts to write beyond the allocated bounds of the fragment array, leading to a kernel panic and system termination.
This vulnerability presents a significant operational risk for systems utilizing the atlantic network driver, particularly in production environments where high-throughput networking is critical. The potential impact includes complete system crashes, service disruption, and denial of service conditions that can affect network availability and overall system reliability. The attack surface is limited to systems running the affected Linux kernel versions with the atlantic driver enabled, but the consequences are severe as they can affect any application relying on network connectivity. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and can be mapped to ATT&CK technique T1499.201, which involves network denial of service attacks through kernel-level vulnerabilities. Organizations using Aquantia AQC113 NICs or similar hardware are particularly at risk, as the issue has been observed in production environments with these specific network adapters.
The fix implemented addresses the vulnerability by modifying the fragment accounting logic to anticipate potential overflow conditions. The solution involves assuming that an extra fragment will be required when buff->len exceeds AQ_CFG_RX_HDR_SIZE, thereby ensuring that all fragments are properly accounted for before any memory operations occur. This approach reuses existing validation checks and implements an earlier prevention mechanism within the code path to avoid the out-of-bounds write condition. The patch ensures that the fragment count is validated before the skb_add_rx_frag() function is called, preventing the array bounds violation that previously led to kernel panics. This mitigation strategy aligns with secure coding practices that emphasize input validation and bounds checking, and it directly addresses the root cause by preventing the condition that leads to memory corruption. The fix is backward compatible and maintains the existing functionality while providing the necessary protection against the overflow condition, making it suitable for deployment in production systems without significant risk of regression.