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net/packet: avoid fanout hook re-registration after unregister

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: net/packet: avoid fanout hook re-registration after unregister packet_set_ring() temporarily detaches a socket from packet delivery while reconfiguring its ring. It records the previous running state, clears po->num, unregisters the protocol hook when needed, drops po->bind_lock, and later restores po->num and re-registers the hook from the saved was_running value. That unlocked window can race with NETDEV_UNREGISTER. The notifier can observe the socket as not running, skip __unregister_prot_hook(), and invalidate the per-socket binding by setting po->ifindex to -1 and clearing po->prot_hook.dev. A one-member fanout group can still retain its shared fanout hook device pointer. When packet_set_ring() resumes, re-registering solely from the stale was_running state can re-add the fanout hook after the device has been unregistered. Treat po->ifindex == -1 as an invalidated binding after reacquiring po->bind_lock. This is distinct from ifindex 0, the normal unbound/wildcard state: ifindex -1 marks an existing device binding that was invalidated when the device was unregistered. Restore po->num as before, but do not re-register the hook if device unregister already detached the socket.

Announced Source revision 1
Original source ↗

CVE-2026-68338

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-2026-68338

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": "dc99f600698dcac69b8f56dda9a8a00d645c5ffc",
        "lessThan": "acb40ebfa5c4d62f84339fcbf713f2a9fd033a71",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "dc99f600698dcac69b8f56dda9a8a00d645c5ffc",
        "lessThan": "c820f4b7f2fa38f8769db0d0cefdd94e2721504d",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "dc99f600698dcac69b8f56dda9a8a00d645c5ffc",
        "lessThan": "4628efbdc7affd094181f5263e65c1062e31f15f",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "dc99f600698dcac69b8f56dda9a8a00d645c5ffc",
        "lessThan": "80ec024d53a05c60ad1d08968dcf745f10c1665c",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "dc99f600698dcac69b8f56dda9a8a00d645c5ffc",
        "lessThan": "0a052e0808e015e68144a9877e6ef42b952c49fa",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "dc99f600698dcac69b8f56dda9a8a00d645c5ffc",
        "lessThan": "1bc55c29cd85818e9052f17deb287d5a11fb817f",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "dc99f600698dcac69b8f56dda9a8a00d645c5ffc",
        "lessThan": "a885387dae7986a55bae5c77a15bdd447f64e9b9",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "dc99f600698dcac69b8f56dda9a8a00d645c5ffc",
        "lessThan": "50aff80475abd3533eef4320477037e6fcc6b56e",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "net/packet/af_packet.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "3.1"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "3.1",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.10.265",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.216",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.183",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.148",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.101",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.42",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.1.6",
        "versionType": "semver",
        "lessThanOrEqual": "7.1.*"
      },
      {
        "status": "unaffected",
        "version": "7.2",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "net/packet/af_packet.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-68338

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#41699 · Revision 1
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Publisher date
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