CVE-2026-98621 (GCVE-0-2026-98621)
Vulnerability from cvelistv5
Published
2026-10-18 15:19
Modified
2026-10-19 09:22
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: net: gue: reject invalid REMCSUM offsets The REMCSUM option carries an absolute checksum start and checksum field offset. gue_remcsum() passes them to skb_remcsum_process(), whose partial path stores offset - start in the u16 skb->csum_offset variable. If offset is less than start, this underflows. A forwarded packet can retain CHECKSUM_PARTIAL and reach a NETIF_F_HW_CSUM driver which trusts the metadata, leading skb_copy_and_csum_dev() to write two bytes about 64 KiB beyond the destination buffer. Reject reversed tuples in validate_gue_flags(), after the existing length validation, so all GUE parsers enforce the ordering in one place.
References
Impacted products
Vendor Product Version
Linux Linux Version: fe881ef11cf0220f118816181930494d484c4883
Version: fe881ef11cf0220f118816181930494d484c4883
Version: fe881ef11cf0220f118816181930494d484c4883
Version: fe881ef11cf0220f118816181930494d484c4883
Version: fe881ef11cf0220f118816181930494d484c4883
Version: fe881ef11cf0220f118816181930494d484c4883
Version: fe881ef11cf0220f118816181930494d484c4883
Version: fe881ef11cf0220f118816181930494d484c4883
 Create a notification for this product.
Show details on NVD website

To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "include/net/gue.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "4b9bc21b2396c396d88dd909caaf73d5be6ff593",
              "status": "affected",
              "version": "fe881ef11cf0220f118816181930494d484c4883",
              "versionType": "git"
            },
            {
              "lessThan": "43efb1f997e976f386aa89716f55870cd2cff9ad",
              "status": "affected",
              "version": "fe881ef11cf0220f118816181930494d484c4883",
              "versionType": "git"
            },
            {
              "lessThan": "1eeec0c51fd5598da44080ed96bbd9880021c28b",
              "status": "affected",
              "version": "fe881ef11cf0220f118816181930494d484c4883",
              "versionType": "git"
            },
            {
              "lessThan": "1d664be4ca49d1696e85239236f4988dfc4653c3",
              "status": "affected",
              "version": "fe881ef11cf0220f118816181930494d484c4883",
              "versionType": "git"
            },
            {
              "lessThan": "97f907203321eee2cc9132d5c9eb47698fb41d35",
              "status": "affected",
              "version": "fe881ef11cf0220f118816181930494d484c4883",
              "versionType": "git"
            },
            {
              "lessThan": "40aeafbcbc7bc4018e8f74bbbb4d29ed8846f57f",
              "status": "affected",
              "version": "fe881ef11cf0220f118816181930494d484c4883",
              "versionType": "git"
            },
            {
              "lessThan": "c20f755338ca234e523dfc943719f194dfc1f903",
              "status": "affected",
              "version": "fe881ef11cf0220f118816181930494d484c4883",
              "versionType": "git"
            },
            {
              "lessThan": "2566866fc30965d915d0b52b5c3323b362619f0e",
              "status": "affected",
              "version": "fe881ef11cf0220f118816181930494d484c4883",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "include/net/gue.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.0"
            },
            {
              "lessThan": "4.0",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.271",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.222",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.189",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.158",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.112",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.55",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.271",
                  "versionStartIncluding": "4.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.222",
                  "versionStartIncluding": "4.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.189",
                  "versionStartIncluding": "4.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.158",
                  "versionStartIncluding": "4.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.112",
                  "versionStartIncluding": "4.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.55",
                  "versionStartIncluding": "4.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.9",
                  "versionStartIncluding": "4.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "4.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: gue: reject invalid REMCSUM offsets\n\nThe REMCSUM option carries an absolute checksum start and checksum field\noffset. gue_remcsum() passes them to skb_remcsum_process(), whose\npartial path stores offset - start in the u16 skb-\u003ecsum_offset variable.\nIf offset is less than start, this underflows.\n\nA forwarded packet can retain CHECKSUM_PARTIAL and reach a NETIF_F_HW_CSUM\ndriver which trusts the metadata, leading skb_copy_and_csum_dev() to write\ntwo bytes about 64 KiB beyond the destination buffer.\n\nReject reversed tuples in validate_gue_flags(), after the existing length\nvalidation, so all GUE parsers enforce the ordering in one place."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T09:22:49.371Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/4b9bc21b2396c396d88dd909caaf73d5be6ff593"
        },
        {
          "url": "https://git.kernel.org/stable/c/43efb1f997e976f386aa89716f55870cd2cff9ad"
        },
        {
          "url": "https://git.kernel.org/stable/c/1eeec0c51fd5598da44080ed96bbd9880021c28b"
        },
        {
          "url": "https://git.kernel.org/stable/c/1d664be4ca49d1696e85239236f4988dfc4653c3"
        },
        {
          "url": "https://git.kernel.org/stable/c/97f907203321eee2cc9132d5c9eb47698fb41d35"
        },
        {
          "url": "https://git.kernel.org/stable/c/40aeafbcbc7bc4018e8f74bbbb4d29ed8846f57f"
        },
        {
          "url": "https://git.kernel.org/stable/c/c20f755338ca234e523dfc943719f194dfc1f903"
        },
        {
          "url": "https://git.kernel.org/stable/c/2566866fc30965d915d0b52b5c3323b362619f0e"
        }
      ],
      "title": "net: gue: reject invalid REMCSUM offsets",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98621",
    "datePublished": "2026-10-18T15:19:41.211Z",
    "dateReserved": "2026-09-25T10:25:14.360Z",
    "dateUpdated": "2026-10-19T09:22:49.371Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.