Medium

Denial of Service via Quadratic Complexity in kjd/idna

Type: advisorySources: OSV

A vulnerability was identified in the kjd/idna library, specifically within the `idna.encode()` function, affecting version 3.6. The issue arises from the function's handling of crafted input strings, which can lead to quadratic complexity and consequently, a denial of service condition. This vulnerability is triggered by a crafted input that causes the `idna.encode()` function to process the input with considerable computational load, significantly increasing the processing time in a quadratic manner relative to the input size.

Products: Not specified
Affected versions: Not specified
Fixed versions: Not specified
CVEs: CVE-2024-3651
Confirmed fixed CVEs: Not specified
Updated in this feed: 7 Nov 2026, 19:38 UTC · Revision 1

Source evidence

Denial of Service via Quadratic Complexity in kjd/idna

core-osv · Original source

Published 7 Jul 2024, 17:22 UTC

osv:CVE-2024-3651

Complete source record

{
  "id": "6b3b0127356a68e792f1b3a7c5106f52f3a885360d9aef5f0a1bd4d99eacc98b",
  "url": "https://osv.dev/vulnerability/CVE-2024-3651",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Denial of Service via Quadratic Complexity in kjd/idna",
    "summary": "A vulnerability was identified in the kjd/idna library, specifically within the `idna.encode()` function, affecting version 3.6. The issue arises from the function's handling of crafted input strings, which can lead to quadratic complexity and consequently, a denial of service condition. This vulnerability is triggered by a crafted input that causes the `idna.encode()` function to process the input with considerable computational load, significantly increasing the processing time in a quadratic manner relative to the input size.",
    "evidence": "osv:CVE-2024-3651",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2024-3651",
      "aliases": [
        "CVE-2024-3651",
        "GHSA-jjg7-2v4v-x38h",
        "PYSEC-2024-60"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/kjd/idna",
              "type": "GIT",
              "events": [
                {
                  "introduced": "001644567c3f1e1c7e62cfff806be7dad1be8cd3"
                },
                {
                  "fixed": "1d365e17e10d72d0b7876316fc7b9ca0eebdd38d"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "3.7"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "SplitRange"
                  },
                  {
                    "range": [
                      {
                        "fixed": "1d365e17e10d72d0b7876316fc7b9ca0eebdd38d"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "cpe": "cpe:2.3:a:kjd:internationalized_domain_names_in_applications:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0.2"
                      },
                      {
                        "fixed": "3.7"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v3.3",
            "v3.2",
            "v3.1",
            "v3.0",
            "v2.10",
            "v2.9",
            "v2.8",
            "v2.7",
            "v2.6",
            "v2.5",
            "v2.4",
            "v2.3",
            "v2.2",
            "v2.1",
            "v2.0",
            "v1.1",
            "v1.0",
            "v0.9",
            "v0.8",
            "v0.7",
            "v0.6",
            "v0.5",
            "v0.4",
            "v0.3",
            "v0.2"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-3651.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:51.492715104Z",
      "provider": "osv",
      "references": [
        "https://huntr.com/bounties/93d78d07-d791-4b39-a845-cbfabc44aadb",
        "https://lists.debian.org/debian-lts-announce/2024/05/msg00006.html",
        "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4YQUPYH3SVZ5GFF2CDQ55FCM575AZTF2/",
        "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/F2S5E23N6E52S46KGNYTDFB75LOC4N4D/",
        "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/S5IDLLD2IKSIVRBSLB34WTSYGLMWUFWF/",
        "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ULSC7HBJKXB3BZV367WM5BR6DFEC4Z43/",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/3xxx/CVE-2024-3651.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2024-3651",
        "https://github.com/kjd/idna/commit/1d365e17e10d72d0b7876316fc7b9ca0eebdd38d"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-1333"
        ],
        "cna_assigner": "@huntr_ai",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/3xxx/CVE-2024-3651.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2024-3651",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 520240,
  "published_at": "2024-07-07T17:22:10.032+00:00"
}