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macvlan: inherit needed_headroom and needed_tailroom from lowerdev

Type: advisorySource: Official CVE List1 source record

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.

Announced Source revision 1
Original source ↗

CVE-2026-74743

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-74743

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53",
        "lessThan": "c2ef3f134b069c54b9cc95cce1a16c38c4939336",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53",
        "lessThan": "7b0eb3e0f363ca79a3af9efd2e87c6258f11da2b",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53",
        "lessThan": "8cd90e850e434577bf6774778657d26d6995e53f",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53",
        "lessThan": "28afc87bd8da0b3348bbbd834c8a89e83712cf5e",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53",
        "lessThan": "8f6a05dbac05725e0786701eb04778c5bdbe4eaa",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53",
        "lessThan": "96fa90b74385b7f2b0d97251dd43d5ee6ca44668",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53",
        "lessThan": "bc9a00fb78e32bccc39d763bfd13a450705bac5d",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "b863ceb7ddcea8c55fcf1d7b2ac591d50aa7ed53",
        "lessThan": "cef51860becd9700217c81732ca1eb1ea6ed6fe1",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "drivers/net/macvlan.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "2.6.23"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "2.6.23",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.10.271",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.222",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.184",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.153",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.105",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.46",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.1.10",
        "versionType": "semver",
        "lessThanOrEqual": "7.1.*"
      },
      {
        "status": "unaffected",
        "version": "7.2",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "drivers/net/macvlan.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-74743

Source reference: /cveMetadata/cveId

Publisher severity

critical

Source reference: /containers/cna/metrics

Event
#34289 · Revision 1
Added to Heist Feed
Publisher date
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