Vulnerability-Lookup

GHSA-4HCM-QG7J-CC3V

Vulnerability from github – Published: 2026-03-18 12:31 – Updated: 2026-03-18 12:31

Details

In the Linux kernel, the following vulnerability has been resolved:

tcp: secure_seq: add back ports to TS offset

This reverts 28ee1b746f49 ("secure_seq: downgrade to per-host timestamp offsets")

tcp_tw_recycle went away in 2017.

Zhouyan Deng reported off-path TCP source port leakage via SYN cookie side-channel that can be fixed in multiple ways.

One of them is to bring back TCP ports in TS offset randomization.

As a bonus, we perform a single siphash() computation to provide both an ISN and a TS offset.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-23247"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-03-18T11:16:16Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: secure_seq: add back ports to TS offset\n\nThis reverts 28ee1b746f49 (\"secure_seq: downgrade to per-host timestamp offsets\")\n\ntcp_tw_recycle went away in 2017.\n\nZhouyan Deng reported off-path TCP source port leakage via\nSYN cookie side-channel that can be fixed in multiple ways.\n\nOne of them is to bring back TCP ports in TS offset randomization.\n\nAs a bonus, we perform a single siphash() computation\nto provide both an ISN and a TS offset.",
  "id": "GHSA-4hcm-qg7j-cc3v",
  "modified": "2026-03-18T12:31:52Z",
  "published": "2026-03-18T12:31:52Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-23247"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/165573e41f2f66ef98940cf65f838b2cb575d9d1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/46e5b0d7cf55821527adea471ffe52a5afbd9caf"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/eae2f14ab2efccdb7480fae7d42c4b0116ef8805"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-23247 (GCVE-0-2026-23247)

Vulnerability from cvelistv5 – Published: 2026-03-18 10:05 – Updated: 2026-04-13 06:03

Title

tcp: secure_seq: add back ports to TS offset

Summary

In the Linux kernel, the following vulnerability has been resolved: tcp: secure_seq: add back ports to TS offset This reverts 28ee1b746f49 ("secure_seq: downgrade to per-host timestamp offsets") tcp_tw_recycle went away in 2017. Zhouyan Deng reported off-path TCP source port leakage via SYN cookie side-channel that can be fixed in multiple ways. One of them is to bring back TCP ports in TS offset randomization. As a bonus, we perform a single siphash() computation to provide both an ISN and a TS offset.

Severity ?

No CVSS data available.

Assigner

Linux

References

URL

Tags

	https://git.kernel.org/stable/c/eae2f14ab2efccdb7…
	https://git.kernel.org/stable/c/46e5b0d7cf5582152…
	https://git.kernel.org/stable/c/165573e41f2f66ef9…

Impacted products

Vendor

Product

Version

Linux

Affected: 28ee1b746f493b7c62347d714f58fbf4f70df4f0 , < eae2f14ab2efccdb7480fae7d42c4b0116ef8805 (git)
Affected: 28ee1b746f493b7c62347d714f58fbf4f70df4f0 , < 46e5b0d7cf55821527adea471ffe52a5afbd9caf (git)
Affected: 28ee1b746f493b7c62347d714f58fbf4f70df4f0 , < 165573e41f2f66ef98940cf65f838b2cb575d9d1 (git)
Affected: 443fac9f2618b93cbc5ab068dc594530236b3a23 (git)

Linux

Affected: 4.11
Unaffected: 0 , < 4.11 (semver)
Unaffected: 6.18.17 , ≤ 6.18.* (semver)
Unaffected: 6.19.7 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "include/net/secure_seq.h",
            "include/net/tcp.h",
            "net/core/secure_seq.c",
            "net/ipv4/syncookies.c",
            "net/ipv4/tcp_input.c",
            "net/ipv4/tcp_ipv4.c",
            "net/ipv6/syncookies.c",
            "net/ipv6/tcp_ipv6.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "eae2f14ab2efccdb7480fae7d42c4b0116ef8805",
              "status": "affected",
              "version": "28ee1b746f493b7c62347d714f58fbf4f70df4f0",
              "versionType": "git"
            },
            {
              "lessThan": "46e5b0d7cf55821527adea471ffe52a5afbd9caf",
              "status": "affected",
              "version": "28ee1b746f493b7c62347d714f58fbf4f70df4f0",
              "versionType": "git"
            },
            {
              "lessThan": "165573e41f2f66ef98940cf65f838b2cb575d9d1",
              "status": "affected",
              "version": "28ee1b746f493b7c62347d714f58fbf4f70df4f0",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "443fac9f2618b93cbc5ab068dc594530236b3a23",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "include/net/secure_seq.h",
            "include/net/tcp.h",
            "net/core/secure_seq.c",
            "net/ipv4/syncookies.c",
            "net/ipv4/tcp_input.c",
            "net/ipv4/tcp_ipv4.c",
            "net/ipv6/syncookies.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": "4.11"
            },
            {
              "lessThan": "4.11",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.17",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.7",
              "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": "6.18.17",
                  "versionStartIncluding": "4.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19.7",
                  "versionStartIncluding": "4.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0",
                  "versionStartIncluding": "4.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "4.10.14",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: secure_seq: add back ports to TS offset\n\nThis reverts 28ee1b746f49 (\"secure_seq: downgrade to per-host timestamp offsets\")\n\ntcp_tw_recycle went away in 2017.\n\nZhouyan Deng reported off-path TCP source port leakage via\nSYN cookie side-channel that can be fixed in multiple ways.\n\nOne of them is to bring back TCP ports in TS offset randomization.\n\nAs a bonus, we perform a single siphash() computation\nto provide both an ISN and a TS offset."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-13T06:03:04.908Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/eae2f14ab2efccdb7480fae7d42c4b0116ef8805"
        },
        {
          "url": "https://git.kernel.org/stable/c/46e5b0d7cf55821527adea471ffe52a5afbd9caf"
        },
        {
          "url": "https://git.kernel.org/stable/c/165573e41f2f66ef98940cf65f838b2cb575d9d1"
        }
      ],
      "title": "tcp: secure_seq: add back ports to TS offset",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-23247",
    "datePublished": "2026-03-18T10:05:09.353Z",
    "dateReserved": "2026-01-13T15:37:45.989Z",
    "dateUpdated": "2026-04-13T06:03:04.908Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date

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-4HCM-QG7J-CC3V

CVE-2026-23247 (GCVE-0-2026-23247)

Tags

Sightings

Nomenclature