CVE-2026-74701

Summary

In the Linux kernel, the following vulnerability has been resolved:

net/openvswitch: check Ethernet header length in key_extract()

When a packet arrives on an ARPHRD_NONE device (e.g. TUN), ovs_flow_key_extract() trusts the user-provided skb->protocol field: if it is ETH_P_TEB, the packet is classified as MAC_PROTO_ETHERNET and key_extract() is called without ensuring the skb has ETH_HLEN (14) bytes of linear data. key_extract() unconditionally pulls 2 * ETH_ALEN bytes for MAC addresses and parse_ethertype() pulls 2 more, either of which triggers a kernel BUG in __skb_pull() when the linear area is too small.

kernel BUG at include/linux/skbuff.h:2848! RIP: 0010:key_extract+0xa7e/0xd90 net/openvswitch/flow.c:933 ovs_flow_key_extract+0x419/0xa70 ovs_vport_receive+0x222/0x390 netdev_frame_hook+0x3e0/0x630 tun_get_user+0x2d0c/0x38e0

Fixed by calling check_header() in key_extract() before accessing the Ethernet header.

Affected Software

Weaknesses

References

• https://git.kernel.org/stable/c/e85278afd4890dd190ba3c7a1b1a712b801c9fe1
• https://git.kernel.org/stable/c/81f9b09f0ea3ba9ab966dd17e9f32625a14555e9
• https://git.kernel.org/stable/c/831471718f6e19aed1a330b03b53190a90e06466
• https://git.kernel.org/stable/c/d8bea341b183190ce6c055ab0e64ab78eb9a7290
• https://git.kernel.org/stable/c/0b60b55652ba772b173dddc63f3851e1d2dd5927
• https://git.kernel.org/stable/c/a8139285c8925efe59af28a9169bb2fda91bff15
• https://git.kernel.org/stable/c/9b8cfbb58b85bfa7a78fac47fdc77396cd01f699
• https://git.kernel.org/stable/c/cf6f8b29befb92173659bcef6a441d274947bfae

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