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CVE PROGRAM SOURCE RECORD9.8 Critical

CVE-2026-74743

macvlan: inherit needed_headroom and needed_tailroom from lowerdev

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Status
Published
Published
Updated
Assigning organization
Linux

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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53 to < c2ef3f134b069c54b9cc95cce1a16c38c4939336affected
  • b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53 to < 7b0eb3e0f363ca79a3af9efd2e87c6258f11da2baffected
  • b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53 to < 8cd90e850e434577bf6774778657d26d6995e53faffected
  • b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53 to < 28afc87bd8da0b3348bbbd834c8a89e83712cf5eaffected
  • b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53 to < 8f6a05dbac05725e0786701eb04778c5bdbe4eaaaffected
  • b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53 to < 96fa90b74385b7f2b0d97251dd43d5ee6ca44668affected
  • b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53 to < bc9a00fb78e32bccc39d763bfd13a450705bac5daffected
  • b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53 to < cef51860becd9700217c81732ca1eb1ea6ed6fe1affected

Linux Linux

Default version status: affected

  • 2.6.23affected
  • 0 to < 2.6.23unaffected
  • 5.10.271 to ≤ 5.10.*unaffected
  • 5.15.222 to ≤ 5.15.*unaffected
  • 6.1.184 to ≤ 6.1.*unaffected
  • 6.6.153 to ≤ 6.6.*unaffected
  • 6.12.105 to ≤ 6.12.*unaffected
  • 6.18.46 to ≤ 6.18.*unaffected
  • 7.1.10 to ≤ 7.1.*unaffected
  • 7.2 to ≤ *unaffected

References