Linux Kernel Vulnerability in TUN and TAP Networking Interfaces
CVE-2026-81000
Key Information:
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What is CVE-2026-81000?
The vulnerability in the Linux kernel's TUN and TAP interfaces arises from incorrect management of packet data when tun_get_user() operates with oversized headroom requests. This flaw can lead to an improper allocation of packet data storage, potentially allowing skb->data to be located outside of its intended memory region. To mitigate this issue, headroom allocations must be constrained to align with one-page skb-head limits and specific header offsets, ensuring safe access to protocol bytes and Ethernet headers. Enhanced measures must be employed to pull required protocol bytes before any operations are executed to maintain the integrity of data handling in both raw-TUN and TAP configurations.
Affected Version(s)
Linux eaea34b23c46bf17b4a5638be69ab3561854f34b
Linux eaea34b23c46bf17b4a5638be69ab3561854f34b < 708e87937de93f445225c134a2e20519f9b4ce60
Linux eaea34b23c46bf17b4a5638be69ab3561854f34b < 18ef24cdb2eba32e38f1d27f2d02b7b4212e8f76
Exploit Proof of Concept (PoC)
PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.