Vulnerability-Lookup

GHSA-533V-MRFX-494R

Vulnerability from github – Published: 2026-10-20 21:31 – Updated: 2026-10-20 21:31

Details

An ftp:// transfer configured with CURLUSESSL_NONE can reuse a pooled FTP control connection that a previous easy handle upgraded with STARTTLS and authenticated using a client certificate. The second handle performs neither a new TLS handshake nor a new FTP login, so the server continues to authorize it under the first handle's certificate identity.

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JSON

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{
  "affected": [],
  "aliases": [
    "CVE-2026-86411"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-20T20:17:25Z",
    "severity": null
  },
  "details": "An `ftp://` transfer configured with `CURLUSESSL_NONE` can reuse a pooled FTP\ncontrol connection that a previous easy handle upgraded with `STARTTLS` and\nauthenticated using a client certificate. The second handle performs neither a\nnew TLS handshake nor a new FTP login, so the server continues to authorize it\nunder the first handle\u0027s certificate identity.",
  "id": "GHSA-533v-mrfx-494r",
  "modified": "2026-10-20T21:31:03Z",
  "published": "2026-10-20T21:31:03Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-86411"
    },
    {
      "type": "WEB",
      "url": "https://hackerone.com/reports/3973190"
    },
    {
      "type": "WEB",
      "url": "https://curl.se/docs/CVE-2026-86411.html"
    },
    {
      "type": "WEB",
      "url": "https://curl.se/docs/CVE-2026-86411.json"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-86411 (GCVE-0-2026-86411)

Vulnerability from cvelistv5 – Published: 2026-10-20 20:02 – Updated: 2026-10-20 20:02

Title

FTP connection reuse inherits client-certificate

Summary

An `ftp://` transfer configured with `CURLUSESSL_NONE` can reuse a pooled FTP control connection that a previous easy handle upgraded with `STARTTLS` and authenticated using a client certificate. The second handle performs neither a new TLS handshake nor a new FTP login, so the server continues to authorize it under the first handle's certificate identity.

Severity

No CVSS data available.

CWE

CWE-488 Exposure of Data Element to Wrong Session

Assigner

curl CNA under the redhat root

CNA scorecard D 46/100 over 59 records in the last 180 days details

References

3 references

URL	Tags
https://curl.se/docs/CVE-2026-86411.json
https://curl.se/docs/CVE-2026-86411.html
https://hackerone.com/reports/3973190

Impacted products

1 product

Vendor	Product	Version
curl	curl	Affected: 8.21.0 , ≤ 8.21.0 (semver)

Credits

Stanislav Fort (Aisle Research) Stefan Eissing

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "curl",
          "vendor": "curl",
          "versions": [
            {
              "lessThanOrEqual": "8.21.0",
              "status": "affected",
              "version": "8.21.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Stanislav Fort (Aisle Research)"
        },
        {
          "lang": "en",
          "type": "remediation developer",
          "value": "Stefan Eissing"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "An `ftp://` transfer configured with `CURLUSESSL_NONE` can reuse a pooled FTP\ncontrol connection that a previous easy handle upgraded with `STARTTLS` and\nauthenticated using a client certificate. The second handle performs neither a\nnew TLS handshake nor a new FTP login, so the server continues to authorize it\nunder the first handle\u0027s certificate identity."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "description": "CWE-488 Exposure of Data Element to Wrong Session",
              "lang": "en"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-20T20:02:03.431Z",
        "orgId": "2499f714-1537-4658-8207-48ae4bb9eae9",
        "shortName": "curl"
      },
      "references": [
        {
          "name": "json",
          "url": "https://curl.se/docs/CVE-2026-86411.json"
        },
        {
          "name": "www",
          "url": "https://curl.se/docs/CVE-2026-86411.html"
        },
        {
          "name": "issue",
          "url": "https://hackerone.com/reports/3973190"
        }
      ],
      "title": "FTP connection reuse inherits client-certificate"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "2499f714-1537-4658-8207-48ae4bb9eae9",
    "assignerShortName": "curl",
    "cveId": "CVE-2026-86411",
    "datePublished": "2026-10-20T20:02:03.431Z",
    "dateReserved": "2026-09-07T12:11:48.560Z",
    "dateUpdated": "2026-10-20T20:02:03.431Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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