Vulnerability-Lookup

GHSA-M4FQ-QC69-83H9

Vulnerability from github – Published: 2026-05-08 15:31 – Updated: 2026-05-11 09:30

Details

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.

Severity

9.4 (Critical)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2026-43383"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-05-08T15:16:49Z",
    "severity": "CRITICAL"
  },
  "details": "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.",
  "id": "GHSA-m4fq-qc69-83h9",
  "modified": "2026-05-11T09:30:31Z",
  "published": "2026-05-08T15:31:26Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-43383"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/02669e2a4d207068edce7e8b5fafd85822018ce6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/345a9530756528d7ca407663d659c3c40e75c3dd"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/46d0d6f50dab706637f4c18a470aac20a21900d3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5d305a95130a8d08b9545e47f1e18d29d59866cb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/821c8751fdeecdeecabeb11704dd33439c9e4bbc"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ae3831b44f477de048287493e184fc3ff913b624"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b502e97e29d791ff7a8051f29a414535739be218"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-43383 (GCVE-0-2026-43383)

Vulnerability from cvelistv5 – Published: 2026-05-08 14:21 – Updated: 2026-05-11 22:23

Title

net/tcp-md5: Fix MAC comparison to be constant-time

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.

Severity

9.4 (Critical)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:H

Assigner

Linux

References

7 references

URL	Tags
https://git.kernel.org/stable/c/821c8751fdeecdeec…
https://git.kernel.org/stable/c/345a9530756528d7c…
https://git.kernel.org/stable/c/5d305a95130a8d08b…
https://git.kernel.org/stable/c/02669e2a4d207068e…
https://git.kernel.org/stable/c/ae3831b44f477de04…
https://git.kernel.org/stable/c/b502e97e29d791ff7…
https://git.kernel.org/stable/c/46d0d6f50dab70663…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: cfb6eeb4c860592edd123fdea908d23c6ad1c7dc , < 821c8751fdeecdeecabeb11704dd33439c9e4bbc (git) Affected: cfb6eeb4c860592edd123fdea908d23c6ad1c7dc , < 345a9530756528d7ca407663d659c3c40e75c3dd (git) Affected: cfb6eeb4c860592edd123fdea908d23c6ad1c7dc , < 5d305a95130a8d08b9545e47f1e18d29d59866cb (git) Affected: cfb6eeb4c860592edd123fdea908d23c6ad1c7dc , < 02669e2a4d207068edce7e8b5fafd85822018ce6 (git) Affected: cfb6eeb4c860592edd123fdea908d23c6ad1c7dc , < ae3831b44f477de048287493e184fc3ff913b624 (git) Affected: cfb6eeb4c860592edd123fdea908d23c6ad1c7dc , < b502e97e29d791ff7a8051f29a414535739be218 (git) Affected: cfb6eeb4c860592edd123fdea908d23c6ad1c7dc , < 46d0d6f50dab706637f4c18a470aac20a21900d3 (git)
Linux	Linux	Affected: 2.6.20 Unaffected: 0 , < 2.6.20 (semver) Unaffected: 5.10.253 , ≤ 5.10.* (semver) Unaffected: 6.1.167 , ≤ 6.1.* (semver) Unaffected: 6.6.130 , ≤ 6.6.* (semver) Unaffected: 6.12.78 , ≤ 6.12.* (semver) Unaffected: 6.18.19 , ≤ 6.18.* (semver) Unaffected: 6.19.9 , ≤ 6.19.* (semver) Unaffected: 7.0 , ≤ * (original_commit_for_fix)

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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": [
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              "versionType": "git"
            },
            {
              "lessThan": "345a9530756528d7ca407663d659c3c40e75c3dd",
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              "versionType": "git"
            },
            {
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              "versionType": "git"
            },
            {
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            {
              "lessThan": "b502e97e29d791ff7a8051f29a414535739be218",
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              "versionType": "git"
            }
          ]
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        {
          "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",
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                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.130",
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                },
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                },
                {
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                  "versionStartIncluding": "2.6.20",
                  "vulnerable": true
                }
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        }
      ],
      "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"
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        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-11T22:23:31.624Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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        {
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      "title": "net/tcp-md5: Fix MAC comparison to be constant-time",
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    "datePublished": "2026-05-08T14:21:30.704Z",
    "dateReserved": "2026-05-01T14:12:56.006Z",
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}

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.

Action not permitted

GHSA-M4FQ-QC69-83H9

CVE-2026-43383 (GCVE-0-2026-43383)

Tags

Sightings

Nomenclature