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

Vulnerability from cvelistv5 – Published: 2026-03-18 10:05 – Updated: 2026-11-05 21:33
VLAI
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.
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-11-05 21:23 UTC
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 6638 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 28ee1b746f493b7c62347d714f58fbf4f70df4f0 , < 025f532d8c5cfac77845e50daab7f478b360f2ac (git)
Affected: 28ee1b746f493b7c62347d714f58fbf4f70df4f0 , < e873e8c16b2fb743a381a9e59c108e63512301ec (git)
Affected: 28ee1b746f493b7c62347d714f58fbf4f70df4f0 , < 5da5662181ef8a251e3ba564903002c2e87de452 (git)
Affected: 28ee1b746f493b7c62347d714f58fbf4f70df4f0 , < eae2f14ab2efccdb7480fae7d42c4b0116ef8805 (git)
Affected: 28ee1b746f493b7c62347d714f58fbf4f70df4f0 , < 46e5b0d7cf55821527adea471ffe52a5afbd9caf (git)
Affected: 28ee1b746f493b7c62347d714f58fbf4f70df4f0 , < 165573e41f2f66ef98940cf65f838b2cb575d9d1 (git)
Affected: 443fac9f2618b93cbc5ab068dc594530236b3a23 (git)
Affected: 4.10.14 , < 4.11 (semver)
guessed Create a notification for this product.
Linux Linux Affected: 4.11
Unaffected: 0 , < 4.11 (semver)
Unaffected: 6.1.191 , ≤ 6.1.* (semver)
Unaffected: 6.6.160 , ≤ 6.6.* (semver)
Unaffected: 6.12.94 , ≤ 6.12.* (semver)
Unaffected: 6.18.17 , ≤ 6.18.* (semver)
Unaffected: 6.19.7 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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            "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\ntcp: secure_seq: a\u00f1adir de nuevo puertos al desplazamiento TS\n\nEsto revierte 28ee1b746f49 (\u0027secure_seq: degradar a desplazamientos de marca de tiempo por host\u0027)\n\ntcp_tw_recycle desapareci\u00f3 en 2017.\n\nZhouyan Deng inform\u00f3 de una fuga de puerto de origen TCP fuera de ruta a trav\u00e9s de un canal lateral de SYN cookie que se puede solucionar de m\u00faltiples maneras.\n\nUna de ellas es traer de vuelta los puertos TCP en la aleatorizaci\u00f3n del desplazamiento TS.\n\nComo ventaja adicional, realizamos un \u00fanico c\u00e1lculo de siphash() para proporcionar tanto un ISN como un desplazamiento TS."
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        "id": "CVE-2026-23247",
        "lastModified": "2026-11-05T22:18:08.477",
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            "tags": [
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          },
          {
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            "tags": [
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            "url": "https://git.kernel.org/stable/c/46e5b0d7cf55821527adea471ffe52a5afbd9caf"
          },
          {
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            "url": "https://git.kernel.org/stable/c/5da5662181ef8a251e3ba564903002c2e87de452"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/e873e8c16b2fb743a381a9e59c108e63512301ec"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
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            ],
            "url": "https://git.kernel.org/stable/c/eae2f14ab2efccdb7480fae7d42c4b0116ef8805"
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        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Modified",
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                "value": "NVD-CWE-noinfo"
              }
            ],
            "source": "nvd@nist.gov",
            "type": "Primary"
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    },
    "redhat_vex": {
      "aggregate_severity": "Low",
      "current_release_date": "2026-11-07T10:43:17+00:00",
      "cve": "CVE-2026-23247",
      "id": "CVE-2026-23247",
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      "product_status:known_affected": "172",
      "product_status:known_not_affected": "28",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: Linux kernel: Information disclosure via off-path TCP source port leakage",
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      "version": "3"
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            "title": "CISA ADP Vulnrichment"
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                "net/ipv6/syncookies.c",
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              ],
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              "versions": [
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        "dateUpdated": "2026-11-05T21:33:32.445Z",
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      },
      "dataType": "CVE_RECORD",
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    }
  }
}



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Sightings

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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.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

JSON
How durations are calculated

Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

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    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.