Security advisory

{
  "id": "6adeb276f17b6d796419a8e1f8e3c60702ae4748008bc40ed75c98fc87da5453",
  "url": "https://osv.dev/vulnerability/CVE-2018-20583",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2018-20583",
    "summary": "Cross-site scripting (XSS) vulnerability in the PHP League CommonMark library versions 0.15.6 through 0.18.x before 0.18.1 allows remote attackers to insert unsafe URLs into HTML (even if allow_unsafe_links is false) via a newline character (e.g., writing javascript as javascri%0apt).",
    "evidence": "osv:CVE-2018-20583",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2018-20583",
      "aliases": [
        "CVE-2018-20583",
        "GHSA-qx76-c53f-5c7q"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/thephpleague/commonmark",
              "type": "GIT",
              "events": [
                {
                  "introduced": "91742543c25fecedc84a4883d2919213e04a73b7"
                },
                {
                  "last_affected": "006af077d4b1b7eb1d9760964f9f984ba188632c"
                },
                {
                  "fixed": "e5029f74ba39e043ce4b3ca6c05dc719d8aafd94"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:thephpleague:commonmark:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0.15.6"
                      },
                      {
                        "last_affected": "0.18.0"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "e5029f74ba39e043ce4b3ca6c05dc719d8aafd94"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "0.18.1"
                  }
                ]
              }
            }
          ],
          "versions": [
            "0.18.0",
            "0.17.4",
            "0.17.2",
            "0.17.0",
            "0.16.0",
            "0.15.7",
            "0.15.6"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2018-20583.json"
          }
        }
      ],
      "modified": "2026-10-20T10:50:07.634258507Z",
      "provider": "osv",
      "references": [
        "https://commonmark.thephpleague.com/changelog/",
        "https://github.com/thephpleague/commonmark/releases/tag/0.18.1",
        "https://github.com/thephpleague/commonmark/issues/337"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2018-20583",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 381307,
  "published_at": "2018-12-30T05:29:00.753+00:00"
}