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net: gue: reject invalid REMCSUM offsets

Type: advisorySource: Official CVE List1 source record

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.

Announced Source revision 1
Original source ↗

CVE-2026-98621

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-2026-98621

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": "fe881ef11cf0220f118816181930494d484c4883",
        "lessThan": "4b9bc21b2396c396d88dd909caaf73d5be6ff593",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "fe881ef11cf0220f118816181930494d484c4883",
        "lessThan": "43efb1f997e976f386aa89716f55870cd2cff9ad",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "fe881ef11cf0220f118816181930494d484c4883",
        "lessThan": "1eeec0c51fd5598da44080ed96bbd9880021c28b",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "fe881ef11cf0220f118816181930494d484c4883",
        "lessThan": "1d664be4ca49d1696e85239236f4988dfc4653c3",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "fe881ef11cf0220f118816181930494d484c4883",
        "lessThan": "97f907203321eee2cc9132d5c9eb47698fb41d35",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "fe881ef11cf0220f118816181930494d484c4883",
        "lessThan": "40aeafbcbc7bc4018e8f74bbbb4d29ed8846f57f",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "fe881ef11cf0220f118816181930494d484c4883",
        "lessThan": "c20f755338ca234e523dfc943719f194dfc1f903",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "fe881ef11cf0220f118816181930494d484c4883",
        "lessThan": "2566866fc30965d915d0b52b5c3323b362619f0e",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "include/net/gue.h"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "4.0"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "4.0",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.10.271",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.222",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.189",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.158",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.112",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.55",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.2.9",
        "versionType": "semver",
        "lessThanOrEqual": "7.2.*"
      },
      {
        "status": "unaffected",
        "version": "7.3",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "include/net/gue.h"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-98621

Source reference: /cveMetadata/cveId

Publisher severity

No explicit severity was provided.

Event
#38640 · Revision 1
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Publisher date
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