CVE-2026-86409 (GCVE-0-2026-86409)
Vulnerability from cvelistv5
Published
2026-10-20 19:57
Modified
2026-10-20 19:57
Severity ?
CWE
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.
References
Impacted products
Vendor Product Version
curl curl Version: 8.21.0   ≤ 8.21.0
Version: 8.20.0   ≤ 8.20.0
Version: 8.19.0   ≤ 8.19.0
Version: 8.18.0   ≤ 8.18.0
Version: 8.17.0   ≤ 8.17.0
Version: 8.16.0   ≤ 8.16.0
Version: 8.15.0   ≤ 8.15.0
Version: 8.14.1   ≤ 8.14.1
Version: 8.14.0   ≤ 8.14.0
Version: 8.13.0   ≤ 8.13.0
Version: 8.12.1   ≤ 8.12.1
Version: 8.12.0   ≤ 8.12.0
Version: 8.11.1   ≤ 8.11.1
Version: 8.11.0   ≤ 8.11.0
Version: 8.10.1   ≤ 8.10.1
Version: 8.10.0   ≤ 8.10.0
Version: 8.9.1   ≤ 8.9.1
Version: 8.9.0   ≤ 8.9.0
Version: 8.8.0   ≤ 8.8.0
Version: 8.7.1   ≤ 8.7.1
Version: 8.7.0   ≤ 8.7.0
Version: 8.6.0   ≤ 8.6.0
Version: 8.5.0   ≤ 8.5.0
Version: 8.4.0   ≤ 8.4.0
Version: 8.3.0   ≤ 8.3.0
Version: 8.2.1   ≤ 8.2.1
Version: 8.2.0   ≤ 8.2.0
Version: 8.1.2   ≤ 8.1.2
Version: 8.1.1   ≤ 8.1.1
Version: 8.1.0   ≤ 8.1.0
Version: 8.0.1   ≤ 8.0.1
Version: 8.0.0   ≤ 8.0.0
Version: 7.88.1   ≤ 7.88.1
Version: 7.88.0   ≤ 7.88.0
Version: 7.87.0   ≤ 7.87.0
Version: 7.86.0   ≤ 7.86.0
Version: 7.85.0   ≤ 7.85.0
Version: 7.84.0   ≤ 7.84.0
Version: 7.83.1   ≤ 7.83.1
Version: 7.83.0   ≤ 7.83.0
Version: 7.82.0   ≤ 7.82.0
Version: 7.81.0   ≤ 7.81.0
Version: 7.80.0   ≤ 7.80.0
Version: 7.79.1   ≤ 7.79.1
Version: 7.79.0   ≤ 7.79.0
Version: 7.78.0   ≤ 7.78.0
Version: 7.77.0   ≤ 7.77.0
Version: 7.76.1   ≤ 7.76.1
Version: 7.76.0   ≤ 7.76.0
Version: 7.75.0   ≤ 7.75.0
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "curl",
          "vendor": "curl",
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              "lessThanOrEqual": "8.9.1",
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              "versionType": "semver"
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              "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"
            },
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              "lessThanOrEqual": "8.4.0",
              "status": "affected",
              "version": "8.4.0",
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            },
            {
              "lessThanOrEqual": "8.3.0",
              "status": "affected",
              "version": "8.3.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.2.1",
              "status": "affected",
              "version": "8.2.1",
              "versionType": "semver"
            },
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              "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"
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            {
              "lessThanOrEqual": "7.81.0",
              "status": "affected",
              "version": "7.81.0",
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              "lessThanOrEqual": "7.80.0",
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              "version": "7.80.0",
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            {
              "lessThanOrEqual": "7.79.1",
              "status": "affected",
              "version": "7.79.1",
              "versionType": "semver"
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            {
              "lessThanOrEqual": "7.79.0",
              "status": "affected",
              "version": "7.79.0",
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            {
              "lessThanOrEqual": "7.78.0",
              "status": "affected",
              "version": "7.78.0",
              "versionType": "semver"
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            {
              "lessThanOrEqual": "7.77.0",
              "status": "affected",
              "version": "7.77.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.76.1",
              "status": "affected",
              "version": "7.76.1",
              "versionType": "semver"
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            {
              "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"
}


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