{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "0.6.2"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "785940181659bf440ba82f1da148fade5087e858"
            },
            {
              "fixed": "efe5039d39ee51f117acd0b01ffd8109ae265c22"
            }
          ],
          "repo": "https://github.com/scrapy/protego",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-wjmf-p669-5m5p"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-1333",
      "CWE-400"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55520.json"
  },
  "details": "Protego is a pure-Python robots.txt parser with support for modern conventions. Prior to 0.6.2, protego._urlpattern._URLPattern._prepare_pattern_for_regex translates every asterisk in an Allow or Disallow directive into a lazy regular-expression wildcard, so a directive containing many asterisks creates exponential backtracking. After protego.Protego.parse processes a crafted robots.txt file, protego.Protego.can_fetch can spend an attacker-controlled period matching a near-miss URL and deny service to the crawler. The vulnerable path is src/protego/_urlpattern.py in the _URLPattern match logic. This issue is fixed in version 0.6.2.",
  "id": "CVE-2026-55520",
  "modified": "2026-09-11T03:30:15.626087069Z",
  "published": "2026-08-28T18:42:38.334Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/scrapy/protego/releases/tag/0.6.2"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55520.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/scrapy/protego/security/advisories/GHSA-wjmf-p669-5m5p"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-55520"
    },
    {
      "type": "FIX",
      "url": "https://github.com/scrapy/protego/commit/785940181659bf440ba82f1da148fade5087e858"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Protego: Exponential backtracking ReDoS in robots.txt URL wildcard matching"
}