{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "3.6.11"
              },
              {
                "fixed": "3.6.25"
              },
              {
                "introduced": "3.7.0"
              },
              {
                "fixed": "3.7.10"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "33219a0af86c41a8db81d37c444f65172bfb3e35"
            },
            {
              "introduced": "04aa6bb4f9776f2ba87e5cd181d250e3610e6419"
            },
            {
              "fixed": "4b18b24b0b002dcc80e0640c6088a87d813de29a"
            },
            {
              "fixed": "2a2349356c01b1b1f7ecddb0c17b30c97f5241e7"
            },
            {
              "fixed": "b5ace8eb5d6779980567f5e75efd2d9e08b7e350"
            }
          ],
          "repo": "https://github.com/traefik/traefik",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-6765-c87h-8mrf"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-287"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/71xxx/CVE-2026-71326.json"
  },
  "details": "Traefik is an open source HTTP reverse proxy and load balancer. From 3.6.11 until 3.6.25 and 3.7.10, Traefik's BasicAuth middleware in pkg/middlewares/auth/basic_auth.go deduplicates concurrent password checks with a singleflight key built from the delimiter-free concatenation of password and secret, allowing an attacker who has a valid credential and the stored hash to authenticate as an unconfigured username when headerField trusts the forwarded identity. This issue is fixed in 3.6.25 and 3.7.10.",
  "id": "CVE-2026-71326",
  "modified": "2026-08-12T03:51:28.175692705Z",
  "published": "2026-08-06T16:34:23.931Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/traefik/traefik/releases/tag/v3.6.25"
    },
    {
      "type": "WEB",
      "url": "https://github.com/traefik/traefik/releases/tag/v3.7.10"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/71xxx/CVE-2026-71326.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/traefik/traefik/security/advisories/GHSA-6765-c87h-8mrf"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-71326"
    },
    {
      "type": "FIX",
      "url": "https://github.com/traefik/traefik/commit/b5ace8eb5d6779980567f5e75efd2d9e08b7e350"
    },
    {
      "type": "FIX",
      "url": "https://github.com/traefik/traefik/pull/13572"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Traefik: BasicAuth singleflight key collision allows authenticated identity spoofing"
}