Security advisory

{
  "id": "021e10f530ac8c06115cb72a2a23ca497926de118ce9e4d4cee15269036367c9",
  "url": "https://osv.dev/vulnerability/CVE-2020-15694",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2020-15694",
    "summary": "In Nim 1.2.4, the standard library httpClient fails to properly validate the server response. For example, httpClient.get().contentLength() does not raise any error if a malicious server provides a negative Content-Length.",
    "evidence": "osv:CVE-2020-15694",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2020-15694",
      "aliases": [
        "CVE-2020-15694"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/nim-lang/nim",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "last_affected": "bf320ed172f74f60fd274338e82bdc9ce3520dd9"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:nim-lang:nim:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "1.2.6"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v1.2.6",
            "v1.2.4",
            "v1.2.2",
            "v1.2.0",
            "v1.0.0",
            "v0.20.0",
            "v0.19.0",
            "v0.18.0",
            "v0.17.2",
            "v0.17.0",
            "v0.16.0",
            "v0.15.2",
            "v0.14.2",
            "v0.15.0",
            "v0.14.0",
            "v0.13.0",
            "v0.12.0",
            "v0.11.2",
            "v0.11.0",
            "v0.10.2",
            "v0.9.4",
            "v0.9.2",
            "v0.9.0",
            "v0.8.14"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2020-15694.json"
          }
        }
      ],
      "modified": "2026-10-20T10:52:02.855660437Z",
      "provider": "osv",
      "references": [
        "https://nim-lang.org/blog/2020/07/30/versions-126-and-108-released.html",
        "https://github.com/nim-lang/Nim/blob/dc5a40f3f39c6ea672e6dc6aca7f8118a69dda99/lib/pure/httpclient.nim#L241",
        "https://consensys.net/diligence/vulnerabilities/nim-httpclient-header-crlf-injection/"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2020-15694",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 383225,
  "published_at": "2020-08-14T19:15:12.677+00:00"
}