CVE-2026-74743
In the Linux kernel, the following vulnerability has been resolved: macvlan: inherit needed_headroom and needed_tailroom from lowerdev macvlan devices inherit hard_header_len from lowerdev during macvlan_init(), but leave needed_headroom and…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.52%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
In the Linux kernel, the following vulnerability has been resolved: macvlan: inherit needed_headroom and needed_tailroom from lowerdev macvlan devices inherit hard_header_len from lowerdev during macvlan_init(), but leave needed_headroom and needed_tailroom set to 0. When the underlying lowerdev requires extra headroom or tailroom for headers/trailers (e.g. macsec, ipsec, wireguard, tunnels, or veth with rx headroom), upper layers calculating packet headroom and tailroom fail to reserve sufficient space. This can result in reallocation overhead, skb headroom underflows, or KASAN slab-use-after-free crashes when dev_hard_header() / macvlan_hard_header() prepends header data or when lower devices append tailroom. Fix this by: 1. Inheriting needed_headroom and needed_tailroom from lowerdev in macvlan_init(). 2. Propagating needed_headroom and needed_tailroom updates to attached macvlans in macvlan_device_event() when receiving NETDEV_FEAT_CHANGE events.
- CVSS 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.52% probability · 43th percentile
- CISA KEV
- Not listed
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/28afc87bd8da0b3348bbbd834c8a89e83712cf5e
- https://git.kernel.org/stable/c/8cd90e850e434577bf6774778657d26d6995e53f
- https://git.kernel.org/stable/c/8f6a05dbac05725e0786701eb04778c5bdbe4eaa
- https://git.kernel.org/stable/c/96fa90b74385b7f2b0d97251dd43d5ee6ca44668
- https://git.kernel.org/stable/c/bc9a00fb78e32bccc39d763bfd13a450705bac5d
- https://git.kernel.org/stable/c/cef51860becd9700217c81732ca1eb1ea6ed6fe1
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.