CVE-2026-43383 (GCVE-0-2026-43383)
Vulnerability from cvelistv5
Published
2026-05-08 14:21
Modified
2026-05-11 22:23
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: net/tcp-md5: Fix MAC comparison to be constant-time To prevent timing attacks, MACs need to be compared in constant time. Use the appropriate helper function for this.
Impacted products
Vendor Product Version
Linux Linux Version: cfb6eeb4c860592edd123fdea908d23c6ad1c7dc
Version: cfb6eeb4c860592edd123fdea908d23c6ad1c7dc
Version: cfb6eeb4c860592edd123fdea908d23c6ad1c7dc
Version: cfb6eeb4c860592edd123fdea908d23c6ad1c7dc
Version: cfb6eeb4c860592edd123fdea908d23c6ad1c7dc
Version: cfb6eeb4c860592edd123fdea908d23c6ad1c7dc
Version: cfb6eeb4c860592edd123fdea908d23c6ad1c7dc
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ipv4/Kconfig",
            "net/ipv4/tcp.c",
            "net/ipv4/tcp_ipv4.c",
            "net/ipv6/tcp_ipv6.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "821c8751fdeecdeecabeb11704dd33439c9e4bbc",
              "status": "affected",
              "version": "cfb6eeb4c860592edd123fdea908d23c6ad1c7dc",
              "versionType": "git"
            },
            {
              "lessThan": "345a9530756528d7ca407663d659c3c40e75c3dd",
              "status": "affected",
              "version": "cfb6eeb4c860592edd123fdea908d23c6ad1c7dc",
              "versionType": "git"
            },
            {
              "lessThan": "5d305a95130a8d08b9545e47f1e18d29d59866cb",
              "status": "affected",
              "version": "cfb6eeb4c860592edd123fdea908d23c6ad1c7dc",
              "versionType": "git"
            },
            {
              "lessThan": "02669e2a4d207068edce7e8b5fafd85822018ce6",
              "status": "affected",
              "version": "cfb6eeb4c860592edd123fdea908d23c6ad1c7dc",
              "versionType": "git"
            },
            {
              "lessThan": "ae3831b44f477de048287493e184fc3ff913b624",
              "status": "affected",
              "version": "cfb6eeb4c860592edd123fdea908d23c6ad1c7dc",
              "versionType": "git"
            },
            {
              "lessThan": "b502e97e29d791ff7a8051f29a414535739be218",
              "status": "affected",
              "version": "cfb6eeb4c860592edd123fdea908d23c6ad1c7dc",
              "versionType": "git"
            },
            {
              "lessThan": "46d0d6f50dab706637f4c18a470aac20a21900d3",
              "status": "affected",
              "version": "cfb6eeb4c860592edd123fdea908d23c6ad1c7dc",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/ipv4/Kconfig",
            "net/ipv4/tcp.c",
            "net/ipv4/tcp_ipv4.c",
            "net/ipv6/tcp_ipv6.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.20"
            },
            {
              "lessThan": "2.6.20",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.253",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.167",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.130",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.78",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.19",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.253",
                  "versionStartIncluding": "2.6.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.167",
                  "versionStartIncluding": "2.6.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.130",
                  "versionStartIncluding": "2.6.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.78",
                  "versionStartIncluding": "2.6.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.19",
                  "versionStartIncluding": "2.6.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19.9",
                  "versionStartIncluding": "2.6.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0",
                  "versionStartIncluding": "2.6.20",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/tcp-md5: Fix MAC comparison to be constant-time\n\nTo prevent timing attacks, MACs need to be compared in constant\ntime.  Use the appropriate helper function for this."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.4,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:H",
            "version": "3.1"
          }
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-11T22:23:31.624Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/821c8751fdeecdeecabeb11704dd33439c9e4bbc"
        },
        {
          "url": "https://git.kernel.org/stable/c/345a9530756528d7ca407663d659c3c40e75c3dd"
        },
        {
          "url": "https://git.kernel.org/stable/c/5d305a95130a8d08b9545e47f1e18d29d59866cb"
        },
        {
          "url": "https://git.kernel.org/stable/c/02669e2a4d207068edce7e8b5fafd85822018ce6"
        },
        {
          "url": "https://git.kernel.org/stable/c/ae3831b44f477de048287493e184fc3ff913b624"
        },
        {
          "url": "https://git.kernel.org/stable/c/b502e97e29d791ff7a8051f29a414535739be218"
        },
        {
          "url": "https://git.kernel.org/stable/c/46d0d6f50dab706637f4c18a470aac20a21900d3"
        }
      ],
      "title": "net/tcp-md5: Fix MAC comparison to be constant-time",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-43383",
    "datePublished": "2026-05-08T14:21:30.704Z",
    "dateReserved": "2026-05-01T14:12:56.006Z",
    "dateUpdated": "2026-05-11T22:23:31.624Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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