FKIE_CVE-2026-98621

Vulnerability from fkie_nvd - Published: 2026-10-18 16:17 - Updated: 2026-10-19 10:19
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
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1d664be4ca49d1696e85239236f4988dfc4653c3
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1eeec0c51fd5598da44080ed96bbd9880021c28b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2566866fc30965d915d0b52b5c3323b362619f0e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/40aeafbcbc7bc4018e8f74bbbb4d29ed8846f57f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/43efb1f997e976f386aa89716f55870cd2cff9ad
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/4b9bc21b2396c396d88dd909caaf73d5be6ff593
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/97f907203321eee2cc9132d5c9eb47698fb41d35
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c20f755338ca234e523dfc943719f194dfc1f903
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "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"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "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."
    }
  ],
  "id": "CVE-2026-98621",
  "lastModified": "2026-10-19T10:19:26.217",
  "metrics": {},
  "published": "2026-10-18T16:17:14.997",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1d664be4ca49d1696e85239236f4988dfc4653c3"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1eeec0c51fd5598da44080ed96bbd9880021c28b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/2566866fc30965d915d0b52b5c3323b362619f0e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/40aeafbcbc7bc4018e8f74bbbb4d29ed8846f57f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/43efb1f997e976f386aa89716f55870cd2cff9ad"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/4b9bc21b2396c396d88dd909caaf73d5be6ff593"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/97f907203321eee2cc9132d5c9eb47698fb41d35"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c20f755338ca234e523dfc943719f194dfc1f903"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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