{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0.1.2"
              },
              {
                "fixed": "0.1.3"
              }
            ],
            "source": [
              "DESCRIPTION",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "c1a084dd5ebe58bebfccb7bb8773f6dc280885bd"
            },
            {
              "fixed": "d515550552873410849ea208fd193e27f00058ad"
            },
            {
              "fixed": "6458fd18a5ba41166d4973214c519e98fe05b72d"
            },
            {
              "fixed": "bc004b70985ae5763901baab3a4e204047899768"
            }
          ],
          "repo": "https://github.com/dashbitco/nimble_zta",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-rj24-g8cc-g7g2"
  ],
  "database_specific": {
    "cna_assigner": "EEF",
    "cwe_ids": [
      "CWE-347"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/91xxx/CVE-2026-91187.json",
    "unresolved_ranges": [
      {
        "extracted_events": [
          {
            "introduced": "bc004b70985ae5763901baab3a4e204047899768"
          },
          {
            "fixed": "6458fd18a5ba41166d4973214c519e98fe05b72d"
          }
        ],
        "source": "AFFECTED_FIELD"
      }
    ]
  },
  "details": "Improper Verification of Cryptographic Signature vulnerability in dashbit nimble_zta allows an unauthenticated remote attacker to authenticate as an arbitrary Cloudflare service token. Applications using the Cloudflare Zero Trust authentication strategy are affected.\n\nverify_token/2 in lib/nimble_zta/cloudflare.ex matches the result of JOSE.JWT.verify/2 against {_, token, _s}, which discards the boolean verification result and returns the decoded token after a failed signature check. The attacker sends a forged JWT in the cf-access-jwt-assertion header, carrying the expected iss claim and the seven service token claims. verify_iss/2 reads the iss claim from the forged token, so it rejects nothing, and the service token path then returns those claims as the authenticated identity.\n\nThis issue affects nimble_zta: from 0.1.2 before 0.1.3.",
  "id": "CVE-2026-91187",
  "modified": "2026-09-26T03:30:28.841126933Z",
  "published": "2026-09-24T13:20:52.974Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://cna.erlef.org/cves/CVE-2026-91187.html"
    },
    {
      "type": "WEB",
      "url": "https://github.com"
    },
    {
      "type": "WEB",
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-91187"
    },
    {
      "type": "WEB",
      "url": "https://repo.hex.pm"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/91xxx/CVE-2026-91187.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/dashbitco/nimble_zta/security/advisories/GHSA-rj24-g8cc-g7g2"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-91187"
    },
    {
      "type": "FIX",
      "url": "https://github.com/dashbitco/nimble_zta/commit/6458fd18a5ba41166d4973214c519e98fe05b72d"
    },
    {
      "type": "FIX",
      "url": "https://github.com/dashbitco/nimble_zta/commit/bc004b70985ae5763901baab3a4e204047899768"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/dashbitco/nimble_zta"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:H/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Improper Verification of Cryptographic Signature in dashbit nimble_zta Cloudflare strategy"
}