CVE-2026-23254 (GCVE-0-2026-23254)

Vulnerability from cvelistv5 – Published: 2026-03-18 17:41 – Updated: 2026-05-11 22:03
VLAI?
Title
net: gro: fix outer network offset
Summary
In the Linux kernel, the following vulnerability has been resolved: net: gro: fix outer network offset The udp GRO complete stage assumes that all the packets inserted the RX have the `encapsulation` flag zeroed. Such assumption is not true, as a few H/W NICs can set such flag when H/W offloading the checksum for an UDP encapsulated traffic, the tun driver can inject GSO packets with UDP encapsulation and the problematic layout can also be created via a veth based setup. Due to the above, in the problematic scenarios, udp4_gro_complete() uses the wrong network offset (inner instead of outer) to compute the outer UDP header pseudo checksum, leading to csum validation errors later on in packet processing. Address the issue always clearing the encapsulation flag at GRO completion time. Such flag will be set again as needed for encapsulated packets by udp_gro_complete().
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: af276a5ac8e938c8b058e3e124073cc1e322d98b , < 9d40a85138568696387ef04cd004c64612a70874 (git)
Affected: 5ef31ea5d053a8f493a772ebad3f3ce82c35d845 , < b83557bc6f560433fe5d727e241069f8db5ba709 (git)
Affected: 5ef31ea5d053a8f493a772ebad3f3ce82c35d845 , < 2e5edb69e5d0e23ef248c56fc977039268c77a7b (git)
Affected: 5ef31ea5d053a8f493a772ebad3f3ce82c35d845 , < 5c2c3c38be396257a6a2e55bd601a12bb9781507 (git)
Affected: dbd9466d323a72e22efe09151253d195d36d3bf6 (git)
Create a notification for this product.
Linux Linux Affected: 6.9
Unaffected: 0 , < 6.9 (semver)
Unaffected: 6.6.124 , ≤ 6.6.* (semver)
Unaffected: 6.12.70 , ≤ 6.12.* (semver)
Unaffected: 6.18.10 , ≤ 6.18.* (semver)
Unaffected: 6.19 , ≤ * (original_commit_for_fix)
Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/core/gro.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "9d40a85138568696387ef04cd004c64612a70874",
              "status": "affected",
              "version": "af276a5ac8e938c8b058e3e124073cc1e322d98b",
              "versionType": "git"
            },
            {
              "lessThan": "b83557bc6f560433fe5d727e241069f8db5ba709",
              "status": "affected",
              "version": "5ef31ea5d053a8f493a772ebad3f3ce82c35d845",
              "versionType": "git"
            },
            {
              "lessThan": "2e5edb69e5d0e23ef248c56fc977039268c77a7b",
              "status": "affected",
              "version": "5ef31ea5d053a8f493a772ebad3f3ce82c35d845",
              "versionType": "git"
            },
            {
              "lessThan": "5c2c3c38be396257a6a2e55bd601a12bb9781507",
              "status": "affected",
              "version": "5ef31ea5d053a8f493a772ebad3f3ce82c35d845",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "dbd9466d323a72e22efe09151253d195d36d3bf6",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/core/gro.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.9"
            },
            {
              "lessThan": "6.9",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.124",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.70",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.10",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.19",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.124",
                  "versionStartIncluding": "6.6.31",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.70",
                  "versionStartIncluding": "6.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.10",
                  "versionStartIncluding": "6.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19",
                  "versionStartIncluding": "6.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "6.8.10",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: gro: fix outer network offset\n\nThe udp GRO complete stage assumes that all the packets inserted the RX\nhave the `encapsulation` flag zeroed. Such assumption is not true, as a\nfew H/W NICs can set such flag when H/W offloading the checksum for\nan UDP encapsulated traffic, the tun driver can inject GSO packets with\nUDP encapsulation and the problematic layout can also be created via\na veth based setup.\n\nDue to the above, in the problematic scenarios, udp4_gro_complete() uses\nthe wrong network offset (inner instead of outer) to compute the outer\nUDP header pseudo checksum, leading to csum validation errors later on\nin packet processing.\n\nAddress the issue always clearing the encapsulation flag at GRO completion\ntime. Such flag will be set again as needed for encapsulated packets by\nudp_gro_complete()."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-11T22:03:18.217Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/9d40a85138568696387ef04cd004c64612a70874"
        },
        {
          "url": "https://git.kernel.org/stable/c/b83557bc6f560433fe5d727e241069f8db5ba709"
        },
        {
          "url": "https://git.kernel.org/stable/c/2e5edb69e5d0e23ef248c56fc977039268c77a7b"
        },
        {
          "url": "https://git.kernel.org/stable/c/5c2c3c38be396257a6a2e55bd601a12bb9781507"
        }
      ],
      "title": "net: gro: fix outer network offset",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-23254",
    "datePublished": "2026-03-18T17:41:00.591Z",
    "dateReserved": "2026-01-13T15:37:45.990Z",
    "dateUpdated": "2026-05-11T22:03:18.217Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-23254",
      "date": "2026-05-14",
      "epss": "0.00025",
      "percentile": "0.07312"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-23254\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-03-18T18:16:23.530\",\"lastModified\":\"2026-03-19T13:25:00.570\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nnet: gro: fix outer network offset\\n\\nThe udp GRO complete stage assumes that all the packets inserted the RX\\nhave the `encapsulation` flag zeroed. Such assumption is not true, as a\\nfew H/W NICs can set such flag when H/W offloading the checksum for\\nan UDP encapsulated traffic, the tun driver can inject GSO packets with\\nUDP encapsulation and the problematic layout can also be created via\\na veth based setup.\\n\\nDue to the above, in the problematic scenarios, udp4_gro_complete() uses\\nthe wrong network offset (inner instead of outer) to compute the outer\\nUDP header pseudo checksum, leading to csum validation errors later on\\nin packet processing.\\n\\nAddress the issue always clearing the encapsulation flag at GRO completion\\ntime. Such flag will be set again as needed for encapsulated packets by\\nudp_gro_complete().\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/2e5edb69e5d0e23ef248c56fc977039268c77a7b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/5c2c3c38be396257a6a2e55bd601a12bb9781507\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/9d40a85138568696387ef04cd004c64612a70874\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/b83557bc6f560433fe5d727e241069f8db5ba709\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.