{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "4.34.0"
              }
            ],
            "source": "AFFECTED_FIELD"
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "f3c686a890e6fa36b92614112e8717832894faa7"
            }
          ],
          "repo": "https://github.com/go-acme/lego",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-qqx8-2xmm-jrv8"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-22"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/40xxx/CVE-2026-40611.json"
  },
  "details": "Let's Encrypt client and ACME library written in Go (Lego). Prior to 4.34.0, the webroot HTTP-01 challenge provider in lego is vulnerable to arbitrary file write and deletion via path traversal. A malicious ACME server can supply a crafted challenge token containing ../ sequences, causing lego to write attacker-influenced content to any path writable by the lego process. This vulnerability is fixed in 4.34.0.",
  "id": "CVE-2026-40611",
  "modified": "2026-07-16T03:30:54.859063594Z",
  "published": "2026-04-21T17:58:35.221Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40611.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:21772"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/security/cve/CVE-2026-40611"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/40xxx/CVE-2026-40611.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/go-acme/lego/security/advisories/GHSA-qqx8-2xmm-jrv8"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-40611"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2460233"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Lego: Arbitrary File Write via Path Traversal in Webroot HTTP-01 Provider"
}