Rouille 0.1.6 - 3.6.2 Reachable Assertion DoS via remove_prefix percent-encoding

{
  "id": "2c658cee027195b2b0b0f875f1a51466096d25bd98dc01f83b2e6509c27124bc",
  "url": "https://osv.dev/vulnerability/CVE-2026-66754",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Rouille 0.1.6 - 3.6.2 Reachable Assertion DoS via remove_prefix percent-encoding",
    "summary": "Rouille 0.1.6 through 3.6.2 contains a reachable assertion vulnerability in the Request::remove_prefix function that allows remote unauthenticated attackers to crash the server by sending a crafted percent-encoded URL. Attackers can send a request whose decoded path matches a configured prefix while the raw percent-encoded path does not, causing the assert! to fail and triggering either a 500 error or full process termination depending on the panic configuration.",
    "evidence": "osv:CVE-2026-66754",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-66754",
      "aliases": [
        "CVE-2026-66754"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/tomaka/rouille",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "last_affected": "536fa0eacaeef93168f3378a0296e3f99da7b3af"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0.1.6"
                      },
                      {
                        "last_affected": "3.6.2"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v3.6.2",
            "v3.6.1",
            "v3.6.0",
            "v3.5.0",
            "v3.4.0",
            "v3.3.1",
            "v3.3.0",
            "v3.2.1",
            "v3.2.0",
            "v3.1.1",
            "v3.1.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-66754.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:22.887434295Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/66xxx/CVE-2026-66754.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-66754",
        "https://www.vulncheck.com/advisories/rouille-reachable-assertion-dos-via-remove-prefix-percent-encoding",
        "https://github.com/tomaka/rouille",
        "https://github.com/theopaid/Remote-Denial-of-Service-via-Reachable-Assertion-in-URL-Prefix-Handling-rouille-"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-617"
        ],
        "cna_assigner": "VulnCheck",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/66xxx/CVE-2026-66754.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-66754",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 489298,
  "published_at": "2026-07-28T16:04:29.604+00:00"
}