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Critical

openvswitch: fix GSO userspace truncation underflow

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: openvswitch: fix GSO userspace truncation underflow OVS_ACTION_ATTR_TRUNC currently stores a delta from the original skb length in OVS_CB(skb)->cutlen. When a later userspace action segments a GSO skb, queue_gso_packets() reuses that delta for each smaller segment. A segment can then reach queue_userspace_packet() with cutlen greater than skb->len, underflowing the length passed to skb_zerocopy(). Store the maximum preserved length instead and bound each consumer against the current skb length. Use U32_MAX as the no-truncation sentinel so the value remains valid if skb geometry changes before a consumer handles it.

Announced Group revision 1
Original source ↗

CVE-2026-68123

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-2026-68123

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": "f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1",
        "lessThan": "50a6a85f3d6b1d22d8436848606cdef5d2c490b4",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1",
        "lessThan": "2623c48cc3a8da9a1886fd8f65c0e348f4406fd6",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1",
        "lessThan": "e211b081901ffca76674082c73eeaed53524c369",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1",
        "lessThan": "a16eaaf7c0b0ccdef6166707d90ffbc6eebf6855",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1",
        "lessThan": "fbfa3ad2ad6f3a5624aba5211c46290fb98cc9dc",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1",
        "lessThan": "100a23b1613e9218e0af654ef102352c713f0263",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1",
        "lessThan": "ea85dbcbe8d4056ecb54352f97743d138ea4c407",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1",
        "lessThan": "4032f8ed10fcb84d41c508dfb04be96589f78dfe",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "net/openvswitch/actions.c",
      "net/openvswitch/datapath.c",
      "net/openvswitch/datapath.h",
      "net/openvswitch/vport.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "4.8"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "4.8",
        "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/openvswitch/actions.c",
      "net/openvswitch/datapath.c",
      "net/openvswitch/datapath.h",
      "net/openvswitch/vport.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-68123

Source reference: /cveMetadata/cveId

Publisher severity

critical

Source reference: /containers/cna/metrics

Event
#41123 · Revision 1
Added to Heist Feed
Publisher date
Read the original announcement

Revision history

  1. CVE-2026-68123 · Revision 1Source updated