CVE-2026-86409 (GCVE-0-2026-86409)

Vulnerability from cvelistv5 – Published: 2026-10-20 19:57 – Updated: 2026-10-20 19:57
VLAI
Title
stale SigV4 headers sent unintended
Summary
Setting `CURLOPT_AWS_SIGV4` to NULL but does not disable SigV4 authentication, contrary to expectations and documentation. A subsequent transfer on the same handle still sends an `Authorization: AWS4-HMAC-SHA256` header to whatever URL isset next, leaking state information.
Severity
No CVSS data available.
Assigner
curl CNA under the redhat root
CNA scorecard D 46/100 over 59 records in the last 180 days details
Impacted products
Vendor Product Version CPE status
curl curl Affected: 8.21.0 , ≤ 8.21.0 (semver)
Affected: 8.20.0 , ≤ 8.20.0 (semver)
Affected: 8.19.0 , ≤ 8.19.0 (semver)
Affected: 8.18.0 , ≤ 8.18.0 (semver)
Affected: 8.17.0 , ≤ 8.17.0 (semver)
Affected: 8.16.0 , ≤ 8.16.0 (semver)
Affected: 8.15.0 , ≤ 8.15.0 (semver)
Affected: 8.14.1 , ≤ 8.14.1 (semver)
Affected: 8.14.0 , ≤ 8.14.0 (semver)
Affected: 8.13.0 , ≤ 8.13.0 (semver)
Affected: 8.12.1 , ≤ 8.12.1 (semver)
Affected: 8.12.0 , ≤ 8.12.0 (semver)
Affected: 8.11.1 , ≤ 8.11.1 (semver)
Affected: 8.11.0 , ≤ 8.11.0 (semver)
Affected: 8.10.1 , ≤ 8.10.1 (semver)
Affected: 8.10.0 , ≤ 8.10.0 (semver)
Affected: 8.9.1 , ≤ 8.9.1 (semver)
Affected: 8.9.0 , ≤ 8.9.0 (semver)
Affected: 8.8.0 , ≤ 8.8.0 (semver)
Affected: 8.7.1 , ≤ 8.7.1 (semver)
Affected: 8.7.0 , ≤ 8.7.0 (semver)
Affected: 8.6.0 , ≤ 8.6.0 (semver)
Affected: 8.5.0 , ≤ 8.5.0 (semver)
Affected: 8.4.0 , ≤ 8.4.0 (semver)
Affected: 8.3.0 , ≤ 8.3.0 (semver)
Affected: 8.2.1 , ≤ 8.2.1 (semver)
Affected: 8.2.0 , ≤ 8.2.0 (semver)
Affected: 8.1.2 , ≤ 8.1.2 (semver)
Affected: 8.1.1 , ≤ 8.1.1 (semver)
Affected: 8.1.0 , ≤ 8.1.0 (semver)
Affected: 8.0.1 , ≤ 8.0.1 (semver)
Affected: 8.0.0 , ≤ 8.0.0 (semver)
Affected: 7.88.1 , ≤ 7.88.1 (semver)
Affected: 7.88.0 , ≤ 7.88.0 (semver)
Affected: 7.87.0 , ≤ 7.87.0 (semver)
Affected: 7.86.0 , ≤ 7.86.0 (semver)
Affected: 7.85.0 , ≤ 7.85.0 (semver)
Affected: 7.84.0 , ≤ 7.84.0 (semver)
Affected: 7.83.1 , ≤ 7.83.1 (semver)
Affected: 7.83.0 , ≤ 7.83.0 (semver)
Affected: 7.82.0 , ≤ 7.82.0 (semver)
Affected: 7.81.0 , ≤ 7.81.0 (semver)
Affected: 7.80.0 , ≤ 7.80.0 (semver)
Affected: 7.79.1 , ≤ 7.79.1 (semver)
Affected: 7.79.0 , ≤ 7.79.0 (semver)
Affected: 7.78.0 , ≤ 7.78.0 (semver)
Affected: 7.77.0 , ≤ 7.77.0 (semver)
Affected: 7.76.1 , ≤ 7.76.1 (semver)
Affected: 7.76.0 , ≤ 7.76.0 (semver)
Affected: 7.75.0 , ≤ 7.75.0 (semver)
guessed Create a notification for this product.
Show details on NVD website

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "curl",
          "vendor": "curl",
          "versions": [
            {
              "lessThanOrEqual": "8.21.0",
              "status": "affected",
              "version": "8.21.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.20.0",
              "status": "affected",
              "version": "8.20.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.19.0",
              "status": "affected",
              "version": "8.19.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.18.0",
              "status": "affected",
              "version": "8.18.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.17.0",
              "status": "affected",
              "version": "8.17.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.16.0",
              "status": "affected",
              "version": "8.16.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.15.0",
              "status": "affected",
              "version": "8.15.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.14.1",
              "status": "affected",
              "version": "8.14.1",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.14.0",
              "status": "affected",
              "version": "8.14.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.13.0",
              "status": "affected",
              "version": "8.13.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.12.1",
              "status": "affected",
              "version": "8.12.1",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.12.0",
              "status": "affected",
              "version": "8.12.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.11.1",
              "status": "affected",
              "version": "8.11.1",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.11.0",
              "status": "affected",
              "version": "8.11.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.10.1",
              "status": "affected",
              "version": "8.10.1",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.10.0",
              "status": "affected",
              "version": "8.10.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.9.1",
              "status": "affected",
              "version": "8.9.1",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.9.0",
              "status": "affected",
              "version": "8.9.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.8.0",
              "status": "affected",
              "version": "8.8.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.7.1",
              "status": "affected",
              "version": "8.7.1",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.7.0",
              "status": "affected",
              "version": "8.7.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.6.0",
              "status": "affected",
              "version": "8.6.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.5.0",
              "status": "affected",
              "version": "8.5.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.4.0",
              "status": "affected",
              "version": "8.4.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.3.0",
              "status": "affected",
              "version": "8.3.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.2.1",
              "status": "affected",
              "version": "8.2.1",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.2.0",
              "status": "affected",
              "version": "8.2.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.1.2",
              "status": "affected",
              "version": "8.1.2",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.1.1",
              "status": "affected",
              "version": "8.1.1",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.1.0",
              "status": "affected",
              "version": "8.1.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.0.1",
              "status": "affected",
              "version": "8.0.1",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.0.0",
              "status": "affected",
              "version": "8.0.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.88.1",
              "status": "affected",
              "version": "7.88.1",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.88.0",
              "status": "affected",
              "version": "7.88.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.87.0",
              "status": "affected",
              "version": "7.87.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.86.0",
              "status": "affected",
              "version": "7.86.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.85.0",
              "status": "affected",
              "version": "7.85.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.84.0",
              "status": "affected",
              "version": "7.84.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.83.1",
              "status": "affected",
              "version": "7.83.1",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.83.0",
              "status": "affected",
              "version": "7.83.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.82.0",
              "status": "affected",
              "version": "7.82.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.81.0",
              "status": "affected",
              "version": "7.81.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.80.0",
              "status": "affected",
              "version": "7.80.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.79.1",
              "status": "affected",
              "version": "7.79.1",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.79.0",
              "status": "affected",
              "version": "7.79.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.78.0",
              "status": "affected",
              "version": "7.78.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.77.0",
              "status": "affected",
              "version": "7.77.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.76.1",
              "status": "affected",
              "version": "7.76.1",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.76.0",
              "status": "affected",
              "version": "7.76.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.75.0",
              "status": "affected",
              "version": "7.75.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Stanislav Fort (Aisle Research)"
        },
        {
          "lang": "en",
          "type": "remediation developer",
          "value": "Viktor Szakats"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Setting `CURLOPT_AWS_SIGV4` to NULL but does not disable SigV4 authentication,\ncontrary to expectations and documentation. A subsequent transfer on the same\nhandle still sends an `Authorization: AWS4-HMAC-SHA256` header to whatever URL\nisset next, leaking state information."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "description": "CWE-201 Information Exposure Through Sent Data",
              "lang": "en"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-20T19:57:01.794Z",
        "orgId": "2499f714-1537-4658-8207-48ae4bb9eae9",
        "shortName": "curl"
      },
      "references": [
        {
          "name": "json",
          "url": "https://curl.se/docs/CVE-2026-86409.json"
        },
        {
          "name": "www",
          "url": "https://curl.se/docs/CVE-2026-86409.html"
        },
        {
          "name": "issue",
          "url": "https://hackerone.com/reports/3973135"
        }
      ],
      "title": "stale SigV4 headers sent unintended"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "2499f714-1537-4658-8207-48ae4bb9eae9",
    "assignerShortName": "curl",
    "cveId": "CVE-2026-86409",
    "datePublished": "2026-10-20T19:57:01.794Z",
    "dateReserved": "2026-09-07T12:11:44.926Z",
    "dateUpdated": "2026-10-20T19:57:01.794Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-86409",
      "date": "2026-10-21",
      "epss": "0.00248",
      "percentile": "0.15147"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "curl",
                "vendor": "curl",
                "versions": [
                  {
                    "lessThanOrEqual": "8.21.0",
                    "status": "affected",
                    "version": "8.21.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "8.20.0",
                    "status": "affected",
                    "version": "8.20.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "8.19.0",
                    "status": "affected",
                    "version": "8.19.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "8.18.0",
                    "status": "affected",
                    "version": "8.18.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "8.17.0",
                    "status": "affected",
                    "version": "8.17.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "8.16.0",
                    "status": "affected",
                    "version": "8.16.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "8.15.0",
                    "status": "affected",
                    "version": "8.15.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "8.14.1",
                    "status": "affected",
                    "version": "8.14.1",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "8.14.0",
                    "status": "affected",
                    "version": "8.14.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "8.13.0",
                    "status": "affected",
                    "version": "8.13.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "8.12.1",
                    "status": "affected",
                    "version": "8.12.1",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "8.12.0",
                    "status": "affected",
                    "version": "8.12.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "8.11.1",
                    "status": "affected",
                    "version": "8.11.1",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "8.11.0",
                    "status": "affected",
                    "version": "8.11.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "8.10.1",
                    "status": "affected",
                    "version": "8.10.1",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "8.10.0",
                    "status": "affected",
                    "version": "8.10.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "8.9.1",
                    "status": "affected",
                    "version": "8.9.1",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "8.9.0",
                    "status": "affected",
                    "version": "8.9.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "8.8.0",
                    "status": "affected",
                    "version": "8.8.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "8.7.1",
                    "status": "affected",
                    "version": "8.7.1",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "8.7.0",
                    "status": "affected",
                    "version": "8.7.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "8.6.0",
                    "status": "affected",
                    "version": "8.6.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "8.5.0",
                    "status": "affected",
                    "version": "8.5.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "8.4.0",
                    "status": "affected",
                    "version": "8.4.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "8.3.0",
                    "status": "affected",
                    "version": "8.3.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "8.2.1",
                    "status": "affected",
                    "version": "8.2.1",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "8.2.0",
                    "status": "affected",
                    "version": "8.2.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "8.1.2",
                    "status": "affected",
                    "version": "8.1.2",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "8.1.1",
                    "status": "affected",
                    "version": "8.1.1",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "8.1.0",
                    "status": "affected",
                    "version": "8.1.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "8.0.1",
                    "status": "affected",
                    "version": "8.0.1",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "8.0.0",
                    "status": "affected",
                    "version": "8.0.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "7.88.1",
                    "status": "affected",
                    "version": "7.88.1",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "7.88.0",
                    "status": "affected",
                    "version": "7.88.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "7.87.0",
                    "status": "affected",
                    "version": "7.87.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "7.86.0",
                    "status": "affected",
                    "version": "7.86.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "7.85.0",
                    "status": "affected",
                    "version": "7.85.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "7.84.0",
                    "status": "affected",
                    "version": "7.84.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "7.83.1",
                    "status": "affected",
                    "version": "7.83.1",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "7.83.0",
                    "status": "affected",
                    "version": "7.83.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "7.82.0",
                    "status": "affected",
                    "version": "7.82.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "7.81.0",
                    "status": "affected",
                    "version": "7.81.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "7.80.0",
                    "status": "affected",
                    "version": "7.80.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "7.79.1",
                    "status": "affected",
                    "version": "7.79.1",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "7.79.0",
                    "status": "affected",
                    "version": "7.79.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "7.78.0",
                    "status": "affected",
                    "version": "7.78.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "7.77.0",
                    "status": "affected",
                    "version": "7.77.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "7.76.1",
                    "status": "affected",
                    "version": "7.76.1",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "7.76.0",
                    "status": "affected",
                    "version": "7.76.0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "7.75.0",
                    "status": "affected",
                    "version": "7.75.0",
                    "versionType": "semver"
                  }
                ]
              }
            ],
            "source": "2499f714-1537-4658-8207-48ae4bb9eae9"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "Setting `CURLOPT_AWS_SIGV4` to NULL but does not disable SigV4 authentication,\ncontrary to expectations and documentation. A subsequent transfer on the same\nhandle still sends an `Authorization: AWS4-HMAC-SHA256` header to whatever URL\nisset next, leaking state information."
          }
        ],
        "id": "CVE-2026-86409",
        "lastModified": "2026-10-20T20:17:25.223",
        "metrics": {},
        "published": "2026-10-20T20:17:25.223",
        "references": [
          {
            "source": "2499f714-1537-4658-8207-48ae4bb9eae9",
            "url": "https://curl.se/docs/CVE-2026-86409.html"
          },
          {
            "source": "2499f714-1537-4658-8207-48ae4bb9eae9",
            "url": "https://curl.se/docs/CVE-2026-86409.json"
          },
          {
            "source": "2499f714-1537-4658-8207-48ae4bb9eae9",
            "url": "https://hackerone.com/reports/3973135"
          }
        ],
        "sourceIdentifier": "2499f714-1537-4658-8207-48ae4bb9eae9",
        "vulnStatus": "Received"
      }
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.


Loading…

Loading…

Loading…

Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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

JSON
Events included in the timeline

Loading timeline…


    Loading…

    Loading…

    Loading…

    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.