Vulnerability-Lookup

CVE-2026-68123 (GCVE-0-2026-68123)

Vulnerability from cvelistv5 – Published: 2026-08-10 11:58 – Updated: 2026-08-10 11:58

Title

openvswitch: fix GSO userspace truncation underflow

Summary

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.

Severity

No CVSS data available.

Assigner

Linux

References

5 references

URL	Tags
https://git.kernel.org/stable/c/a16eaaf7c0b0ccdef…
https://git.kernel.org/stable/c/fbfa3ad2ad6f3a562…
https://git.kernel.org/stable/c/100a23b1613e9218e…
https://git.kernel.org/stable/c/ea85dbcbe8d4056ec…
https://git.kernel.org/stable/c/4032f8ed10fcb84d4…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 , < a16eaaf7c0b0ccdef6166707d90ffbc6eebf6855 (git) Affected: f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 , < fbfa3ad2ad6f3a5624aba5211c46290fb98cc9dc (git) Affected: f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 , < 100a23b1613e9218e0af654ef102352c713f0263 (git) Affected: f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 , < ea85dbcbe8d4056ecb54352f97743d138ea4c407 (git) Affected: f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 , < 4032f8ed10fcb84d41c508dfb04be96589f78dfe (git)
Linux	Linux	Affected: 4.8 Unaffected: 0 , < 4.8 (semver) Unaffected: 6.6.148 , ≤ 6.6.* (semver) Unaffected: 6.12.101 , ≤ 6.12.* (semver) Unaffected: 6.18.42 , ≤ 6.18.* (semver) Unaffected: 7.1.6 , ≤ 7.1.* (semver) Unaffected: 7.2-rc5 , ≤ * (original_commit_for_fix)

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JSON

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{
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        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/openvswitch/actions.c",
            "net/openvswitch/datapath.c",
            "net/openvswitch/datapath.h",
            "net/openvswitch/vport.c"
          ],
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              "versionType": "semver"
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              "versionType": "semver"
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              "status": "unaffected",
              "version": "6.18.42",
              "versionType": "semver"
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              "versionType": "semver"
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            {
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      "providerMetadata": {
        "dateUpdated": "2026-08-10T11:58:43.727Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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        },
        {
          "url": "https://git.kernel.org/stable/c/4032f8ed10fcb84d41c508dfb04be96589f78dfe"
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      ],
      "title": "openvswitch: fix GSO userspace truncation underflow",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-68123",
    "datePublished": "2026-08-10T11:58:43.727Z",
    "dateReserved": "2026-07-30T09:28:09.369Z",
    "dateUpdated": "2026-08-10T11:58:43.727Z",
    "state": "PUBLISHED"
  },
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  }
}

GHSA-WF82-H5XG-M662

Vulnerability from github – Published: 2026-08-10 15:33 – Updated: 2026-08-10 15:33

Details

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.

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-68123"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-10T13:19:57Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nopenvswitch: fix GSO userspace truncation underflow\n\nOVS_ACTION_ATTR_TRUNC currently stores a delta from the original skb\nlength in OVS_CB(skb)-\u003ecutlen. When a later userspace action segments a\nGSO skb, queue_gso_packets() reuses that delta for each smaller segment.\nA segment can then reach queue_userspace_packet() with cutlen greater\nthan skb-\u003elen, underflowing the length passed to skb_zerocopy().\n\nStore the maximum preserved length instead and bound each consumer\nagainst the current skb length. Use U32_MAX as the no-truncation\nsentinel so the value remains valid if skb geometry changes before a\nconsumer handles it.",
  "id": "GHSA-wf82-h5xg-m662",
  "modified": "2026-08-10T15:33:37Z",
  "published": "2026-08-10T15:33:36Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-68123"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/100a23b1613e9218e0af654ef102352c713f0263"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4032f8ed10fcb84d41c508dfb04be96589f78dfe"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a16eaaf7c0b0ccdef6166707d90ffbc6eebf6855"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ea85dbcbe8d4056ecb54352f97743d138ea4c407"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fbfa3ad2ad6f3a5624aba5211c46290fb98cc9dc"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.

Action not permitted

CVE-2026-68123 (GCVE-0-2026-68123)

GHSA-WF82-H5XG-M662

Tags

Sightings

Nomenclature