Avoid quadratic complexity in resolvePath in net/url

{
  "id": "0bb7df498e2984b23efcdb2031d6c4e0efa804b0791ffd46814bb4dea49656ee",
  "url": "https://osv.dev/vulnerability/GO-2026-6218",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Avoid quadratic complexity in resolvePath in net/url",
    "summary": "Previously, resolving relative paths containing parent directory ('..') segments performed string conversions and buffer rewrites on each step, resulting in quadratic time complexity and high memory allocation overhead. Now, path resolution operates on a byte buffer using index-based backtracking for '..' segments, eliminating the quadratic time complexity and significantly reducing memory allocations.",
    "evidence": "osv:GO-2026-6218",
    "products": [
      {
        "name": {
          "value": "stdlib",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1.25.13",
            "evidence": "/affected/0/ranges"
          },
          {
            "value": "1.26.6",
            "evidence": "/affected/0/ranges"
          },
          {
            "value": "1.27.0-rc.3",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "GO-2026-6218",
      "aliases": [
        "BIT-golang-2026-56860",
        "CVE-2026-56860",
        "GO-2026-6218"
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1.25.13"
                },
                {
                  "introduced": "1.26.0-0"
                },
                {
                  "fixed": "1.26.6"
                },
                {
                  "introduced": "1.27.0-0"
                },
                {
                  "fixed": "1.27.0-rc.3"
                }
              ]
            }
          ],
          "package": {
            "name": "stdlib",
            "purl": "pkg:golang/stdlib",
            "ecosystem": "Go"
          },
          "database_specific": {
            "source": "https://vuln.go.dev/ID/GO-2026-6218.json"
          },
          "ecosystem_specific": {
            "imports": [
              {
                "path": "net/url",
                "symbols": [
                  "URL.Parse",
                  "URL.ResolveReference",
                  "resolvePath"
                ]
              }
            ]
          }
        }
      ],
      "modified": "2026-10-20T10:42:24.481986669Z",
      "provider": "osv",
      "references": [
        "https://go.dev/cl/803681",
        "https://go.dev/issue/80494",
        "https://groups.google.com/g/golang-announce/c/94pEornpRlI"
      ],
      "provider_metadata": {
        "url": "https://pkg.go.dev/vuln/GO-2026-6218",
        "review_status": "REVIEWED"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-56860",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 379197,
  "published_at": "2026-08-13T21:43:54+00:00"
}