Linux Kernel OVS key_extract Header Length Check Bug
CVE-2026-74701 Published on August 22, 2026
net/openvswitch: check Ethernet header length in key_extract()
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.
Products Associated with CVE-2026-74701
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Affected Versions
Linux:- Version 217ac77a3c2524d999730b2a80b61fcc2d0f734a and below e85278afd4890dd190ba3c7a1b1a712b801c9fe1 is affected.
- Version 217ac77a3c2524d999730b2a80b61fcc2d0f734a and below 81f9b09f0ea3ba9ab966dd17e9f32625a14555e9 is affected.
- Version 217ac77a3c2524d999730b2a80b61fcc2d0f734a and below 831471718f6e19aed1a330b03b53190a90e06466 is affected.
- Version 217ac77a3c2524d999730b2a80b61fcc2d0f734a and below d8bea341b183190ce6c055ab0e64ab78eb9a7290 is affected.
- Version 217ac77a3c2524d999730b2a80b61fcc2d0f734a and below 0b60b55652ba772b173dddc63f3851e1d2dd5927 is affected.
- Version 217ac77a3c2524d999730b2a80b61fcc2d0f734a and below a8139285c8925efe59af28a9169bb2fda91bff15 is affected.
- Version 217ac77a3c2524d999730b2a80b61fcc2d0f734a and below 9b8cfbb58b85bfa7a78fac47fdc77396cd01f699 is affected.
- Version 217ac77a3c2524d999730b2a80b61fcc2d0f734a and below cf6f8b29befb92173659bcef6a441d274947bfae is affected.
- Version 4.10 is affected.
- Before 4.10 is unaffected.
- Version 5.10.265, <= 5.10.* is unaffected.
- Version 5.15.216, <= 5.15.* is unaffected.
- Version 6.1.183, <= 6.1.* is unaffected.
- Version 6.6.152, <= 6.6.* is unaffected.
- Version 6.12.104, <= 6.12.* is unaffected.
- Version 6.18.45, <= 6.18.* is unaffected.
- Version 7.1.9, <= 7.1.* is unaffected.
- Version 7.2, <= * is unaffected.